STANDAR NASIONAL INDONESIA
DAFTAR STANDAR NASIONAL INDONESIA (SNI)
BIDANG BAHAN KONSTRUKSI BANGUNAN DAN REKAYASA SIPIL
1. Metode Pengujian Kuat Tekan Dinding Pasangan Bata Merah di Laboratorium
SNI 03-4164-1996
Metode ini digunakan untuk memperoleh nilai kuat tekan dinding pasangan bata merah yang digunakan sebagai dinding struktural bagi keperluan perencana dan pelaksana
2. Metode Pengujian Kuat Lentur Dinding Pasangan Bata Merah di Laboratorium
SNI 03-4165- 1996
Metode ini digunakan untuk memperoleh nilai kuat lentur dinding pasangan bata merah yang digunakan sebagai dinding struktural bagi keperluan perencana dan pelaksana
3. Metode Pengujian Kuat Geser Dinding Pasangan Bata Merah di Laboratorium
SNI 03-4166-1996
Metode ini digunakan untuk memperoleh nilai kuat geser dinding pasangan bata merah yang digunakan sebagai dinding struktural bagi keperluan perencana dan pelaksana
4. Metode Pengujian Kedataran dan Kerataan Lantai Mengguna-kan Sistem Bilangan F
SNI 03-6435- 2000
Metode ini digunakan untuk pengukuran profil permukaan lantai untuk memperoleh perkiraan
karakteristik kedataran dan perataan permukaan lantai menggunakan sistem bilangan –F dalam satuan metrik
(SI)
5. Metode Pengujian Pembebanan Lantai Beton Bertulang Pada Bangunan Bertingkat dengan Beban Air
SNI 03-6760- 2002
Metode ini digunakan untuk memperoleh nilai lendutan nyata, derajat pemulihan dan kapasitas nyata dari nilai
setelah diberi beban uji
6. Metode Pengujian untuk Tiang Tunggal terhadap Beban Tarik Aksial Statis
SNI 03-6761-2002
Metode ini digunakan untuk menentukan response tiang atau tiang-tiang dalam kelompok tiang terhadap beban aksial tarik dan dapat digunakan semua kedalaman tiang.
7. Metode Pengujian Beban -Lateral pada Pondasi Tiang
SNI 03-6762-2002
Metode ini digunakan untuk pengujian tiang vertical dan tiang miring, baik tiang pancang atau kelompok tiang untuk menentukan hubungan beban lendutan pada saat menerima beban lateral.
8. Spesifikasi Pipa Baja yang Dilas dan Tanpa Sambungan dengan Lapis Hitam dan Galvanis Panas
SNI 07-0242.1-2000
Spesifikasi ini meliputi pipa baja untuk pengguna umum yang dilas tanpa sambungan dengan lapisan hitam dan galvanis panas dalam ukuran tipikal 1/8 inci (3,175 mm) sampai 16 inci (406,40 mm), untuk tiga ukuran tipikal pipa baja dengan berat standar ujung polos, galvanis secara panas, dilas untuk penggunaan dengan
hubungan tipe solder dalam penerapan umum.
9. Spesifikasi Tabung Baja Karbon Struktural Berbentuk Bulat dan Lainnya yang Dibentuk Dalam Keadaan Dingin dengan Dilas Tanpa Kampuh
SNI 07-6402-2000
Spesifikasi ini mencakup baja karbon yang dibuat dalam keadaan dingin dengan dilas dan tanpa kampuh berbentuk bulat, bujursangkar, empat persegi atau tabung structural berbentuk khusus untuk konstruksi jembatan, bangunan gedung dan bangunan umum lainnya yang dilas, dipaku keling atau bulat
10. Spesifikasi Pelat Baja Karbon dengan Kuat Tarik Rendah dan Medium.
SNI 07-6403-2000
Spesifikasi ini ditujukan untuk pelat baja karbon struktural - bermutu A,B,C dan D
11. Spesifikasi Tabung Baja Karbon Struktural yang Dibentuk Dalam
SNI 03-6763-2002
Spesifikasi ini mencakup baja karbon yang dibentuk dalam keadaan panas dengan dilas dan tanpa kampuh untuk tabung baja karbon berbentuk bujur sangkar, STANDAR NASIONAL INDONESIA
No. Judul Standar Nomor Standar Ruang Lingkup Keadaan Panas dengan Dilas Tanpa Kampuh bulat, empat persegi atau tabung struktur berbentuk khusus untuk konstruksi jembatan, bangunan gedung dan bangunan umu lainnya yang dilas, dipaku keeling atau baut
12. Spesifikasi Baja Struktural
SNI 03-6764-2002
1. Spesifikasi ini mencakup penampang baja karbon, pelat dan tulangan berkualitas struktural untuk digunakan dalam konstruksi baja dan bangunan dengan paku keling, baut atau las dan untuk tujuan struktural umum
2. Pemakai harus mnempertimbangkan persyaratan tambahan, seperti ukuran kehaluran austenitic dan persyaratan, charpy V – Notch Impact, bila kelompok 4 atau 5 profil bersayap lebar disyaratkan untuk
digunakan selain kolom atau batang tekan lainnya.
13. Spesifikasi beton struktural
SNI 03-6880-2002
Spesifikasi ini mencakup bahan dan proporsi beton, baja tulangan dan prategang, produksi pengecoran dan
perawatan beton serta konstruksi cetakan. Ditetapkan pula perlakuan siar dan bagian-bagian tertanam,
perbaikan permukaan beton, dan finising permukaan yang tercetak. Dalam beberapa pasal terpisah dibahas
untuk konstruksi pelat dan finisingnya, beton arsitektural, beton masif, dan bahan beserta cara pelaksanaan
konstruksi beton pasca tarik. Termasuk pula ketentuan mengenai pengujian, evaluasi dan penerimaan beton
beserta strukturnya.
Tata Cara
14. Tata Cara
Perencanaan Beton
Bertulang dan Struktur
Dinding Bertulang
Untuk Rumah dan
Gedung
SNI 03-1734-
1989
Tata cara ini digunakan untuk mempersingkat waktu
perencanaan berbagai bentuk struktur yang umum dan
menjamin syarat-syarat perencanaan tahan gempa
untuk rumah dan gedung yang berlaku
15. Tata Cara
Penghitungan Struktur
Beton Untuk
Bangunan Gedung
SNI 03-2847-
1992
Tata cara ini digunakan dalam perencanaan dan
pelaksanaan struktur beton untuk bangunan gedung,
atau struktur bangunan lain yang mempunyai kesamaan
karakter dengan struktur bangunan gedung
16. Tata Cara Perencanaan Dinding Struktur Pasangan Blok Beton Berongga Bertulang Untuk Bangunan Rumah dan Gedung
SNI 03-3430-1994
Tata cara ini digunakan dalam perencanaan dan pelaksanaan bangunan yang menggunakan struktur pasangan blok beton berongga bertulang
17. Tata Cara Pemasangan Panel Beton Ringan Berserat.
SNI 03-3445-1994
Tata cara ini digunakan dalam pemasangan panel beton ringan berserat non struktural sesuai perencanaan yang mengacu pada koordinasi modular.
Kamis, 30 Desember 2010
construction...( translate by your self )
Construction
In large construction projects such as skyscrapers, crane machines are essential.
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of multitasking. Normally the job is managed by the project manager and supervised by the construction manager, design engineer, construction engineer or project architect.
For the successful execution of a project, effective planning is essential. Those involved with the design and execution of the infrastructure in question must consider the environmental impact of the job, the successful scheduling, budgeting, site safety, availability of materials, logistics, inconvenience to the public caused by construction delays, preparing tender documents, etc.Contents [hide]
1 Types of construction projects
1.1 Building construction
1.1.1 Procurement
1.1.1.1 Design and build
1.1.1.2 Management procurement systems
1.2 Residential construction
1.3 Heavy/Civil construction
2 Authority having jurisdiction
3 Routes into construction careers
4 Industrial construction
5 Design team
6 Financial advisors
7 Legal considerations
8 Interaction of expertise
9 History
10 See also
11 References
12 External links
In general, there are three types of construction:
Building construction
Heavy/highway construction
Industrial construction
Each type of construction project requires a unique team to plan, design, construct, and maintain the project.
Building construction for several apartment blocks. The blue material is insulation cladding, which will be covered later.
A large unfinished building.
Building construction is the process of adding structure to real property. The vast majority of building construction projects are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project. However, all building construction projects include some elements in common - design, financial, and legal considerations. Many projects of varying sizes reach undesirable end results, such as structural collapse, cost overruns, and/or litigatios reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.
Building construction is procured privately or publicly utilizing various delivery methodologies, including hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.
Procurement describes the merging of activities undertaken by the client to obtain a building. There are many different methods of construction procurement; however the three most common types of procurement are:
Traditional (Design-bid-build)
Design and Build
Management Contracting
This approach has become more common in recent years and includes an entire completed package, including fixtures, fittings and equipment where necessary, to produce a completed fully functional building. In some cases, the Design and Build (D & B) package can also include finding the site, arranging funding and applying for all necessary statutory consents.
The owner produces a list of requirements for a project, giving an overall view of the project's goals. Several D&B contractors present different ideas about how to accomplish these goals. The owner selects the ideas (s)he likes best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once a contractor (or a consortium) has been hired, they begin building the first phase of the project. As they build phase 1, they design phase 2. This is in contrast to a design-bid-build contract, where the project is completely designed by the owner, then bid on, then completed.
Kent Hansen, director of engineering for the National Asphalt Pavement Association (NAPA), pointed out that state departments of transportation (DOTs) usually use design build contracts as a way of getting projects done when states don't have the resources. In DOTs, design build contracts are usually used for very large projects.
In this arrangement the client plays an active role in the procurement system by entering into separate contracts with the designer (architect or engineer), the construction manager, and individual trade contractors. The client takes on the contractual role, while the construction or project manager provides the active role of managing the separate trade contracts, and ensuring that they all work smoothly and effectively together.
Management procurement systems are often used to speed up the procurement processes, allow the client greater flexibility in design variation throughout the contract, the ability to appoint individual work contractors, separate contractual responsibility on each individual throughout the contract, and to provide greater client control.
More and more families are looking into building their own homes, or contracting to have them built. Construction practices, technologies, and resources conform to state and local building codes.
Workers surveying a road construction project
Heavy/Civil construction is the process adding infrastructure to our built environment. Owners of these projects are usually government agencies, either at the national or local level. As in building construction, heavy/civil construction has design, financial, and legal considerations, however these projects are not usually undertaken for-profit, but to service the public interest. However, heavy/civil construction projects are also undertaken by large private corporations, including, among others, the golf courses, harbors, power companies, railroads, and mines, who undertake the construction of access roads, dams, railroads, general site grading, and massive earthwork projects. As in building construction, the owner will assemble a team to create an overall plan to ensure that the goals of the project are met.
Authority having jurisdiction
In construction, the authority having jurisdiction (AHJ) is the governmental agency or subagency which regulates the construction process. In most cases, this is the municipality in which the building is located. However, construction performed for supra-municipal authorities are usually regulated directly by the owning authority, which becomes the AHJ.
During the planning of a building, the zoning and planning boards of the AHJ will review the overall compliance of the proposed building with the municipal General Plan and zoning regulations. Once the proposed building has been approved, detailed civil, architectural, and structural plans must be submitted to the municipal building department (and sometimes the public works department) to determine compliance with the building code and sometimes for fit with existing infrastructure. Often, the municipal fire department will review the plans for compliance with fire-safety ordinances and regulations.
Construction on a building in Kansas City
Before the foundation can be dug, contractors are typically required to notify utility companies, either directly or through a company such as Dig Safe to ensure that underground utility lines can be marked. This lessens the likelihood of damage to the existing electrical, water, sewage, phone, and cable facilities, which could cause outages and potentially hazardous situations. During the construction of a building, the municipal building inspector inspects the building periodically to ensure that the construction adheres to the approved plans and the local building code. Once construction is complete and a final inspection has been passed, an occupancy permit may be issued.
An operating building must remain in compliance with the fire code. The fire code is enforced by the local fire department.
Any changes made to a building including its use, expansion, its structural integrity, and fire protection items, require acceptance by the AHJ. Anything affecting basic safety functions, no matter how small they may appear, may require the owner to apply for a building permit, to ensure proper review of the contemplated changes against the building code.
Routes into construction careers
There are several routes to the different careers within the construction industry. Craft industries offer jobs where employees train while they work through apprenticeships and other training schemes. Another way, where many construction staff have found success, is through recruitment agencies.
Iron workers hard at work
Technical occupations in the UK require GCSE qualifications or vocational equivalents, either initially or through on the job apprenticeship training. One example is that of Quantity Surveying. Quantity Surveyors are effectively cost managers within the construction industry and may be: (1) employed by Chartered Surveyor practices (referred to often as "PQS" derived from the term Private Quantity Surveyor) who normally represent the client's interest and liaise with the Architect on the client's team, preparing cost plans, preparing tender documentation, giving cost advice on variations, preparing monthly valuation payments to the contractor, agreeing the final account with the contractor, generally looking after the client's interests (although the role can be referred to within some standard forms of contract as being a neutral role to value 'the' costs of the project), in practice it tends to be looking after the client's interests primarily; or (2) employed by Main Contractors, in which role they manage the contractor's costs, place subcontract orders, make payments to subcontractors, claim monthly valuations from the client's surveyor (Private QS or "PQS"), cost manage variations, prepare internal cost reports to senior management and directors, generally managing the project commercially and protect the contractor's interests contractually. Contractual aspects such as delays and extensions of time issues are also within the remit of the Quantity Surveyor (QS); or
(3) employed by Subcontractors, in which role they carry out a similar function to Main Contractor's QS's. The main difference is that they are normally submitting monthly valuation claims for payment to the Main Contractor, whereas the Manin Contractor claims from the client's Surveyor (usually a Chartered Surveyor practice or Private QS "PQS"). Large subcontractors may also employ sub-subcontractors, thereby making the QS role similar in the cost management role, including placing sub-contract orders (to sub-subcontractors), valuing and claiming variations, preparing cost reports to senior management, etc; or
A Habitat for Humanity volunteer installs metal hurricane strapping on a build site in Bunnell, Florida
(4) employed by Local Authorities (local Councils, etc), whereby the role is broadly similar to that of private practice surveyors in cost managing project from the funding client's perspective (in this case the Local Authority council within which they are employed), dealing usually with main contractors; or (5) employed by Developers; whereby the role may be a mixture of the role of a client's surveyor (the funding client being the developer in this case) mixed with that of a main contractor in possibly employing package sub-contractors directly Other information: The most recognised body for surveyors in construction is the Royal Institution of Chartered Surveyors (the 'RICS'). It is more common for a private practice surveyor or local authority employed surveyor to be a member of the RICS, though RICS qualified surveyors do work within main contractors and sub-contractors (the writer of this Quantity Surveyor segment qualified RICS within private practice working on the client's side, then migrated over to work for a large sub-contractor. Such cross-overs are quite common between client's side and contracting). Quantity Surveying offers a great diversity of roles and in career path, working on a variety of projects and within different areas and facets of the construction industry. The qualification of "Chartered Quantity Surveyor" has been superseded as the RICS rules have replaced this with simply "Chartered Surveyor" (except those existing Chartered QS's who registered to keep the Chartered QS title by a date now passed), and Chartered Quantity Surveyor practices have now largely adopted the title of "Construction Cost Consultants" and having the right to call themselves simply "Chartered Surveyors" - though still often referred to in the UK construction industry as "PQS's". It is also possible for Construction Cost Consultant practices to be occasionally employed by local authorities, contractors or subcontractors, on a particular construction project although not if they are already employed as surveyors for the same construction project.
As well as the role of Quantity Surveyor, other professions within the UK construction industry are for example: Architect, Engineer, Project Manager, Planner, Safety Officer. These roles may be in 'Building' (buildings such as Offices, Shopping Centres, Housing); or 'Civil Engineering' (structures such as Bridges, Dams, Motorways/Roads/Highways, Harbours/Ferry Terminals). While projects such as construction of new Power Stations or Naval Bases may comprise a combination of both 'building' and 'civil engineering'.
Graduate roles in the construction industry are filled by people with at least a foundation degree in subjects such as civil engineering, building and construction management. Graduates often receive specialised positions and gain qualifications such as chartered status.
Industrial construction
Industrial construction, though a relatively small part of the entire construction industry, is a very important component. Owners of these projects are usually large, for-profit, industrial corporations. These corporations can be found in such industries as medicine, petroleum, chemical, power generation, manufacturing, etc. Processes in these industries require highly specialized expertise in planning, design, and construction. As in building and heavy/highway construction, this type of construction requires a team of individuals to ensure a successful project.
A construction crew
In the modern industrialized world, construction usually involves the translation of paper or computer based designs into reality. A formal design team may be assembled to plan the physical proceedings, and to integrate those proceedings with the other parts. The design usually consists of drawings and specifications, usually prepared by a design team including architects, interior designers, surveyors, civil engineers, cost engineers (or quantity surveyors), mechanical engineers, electrical engineers, structural engineers, and fire protection engineers.[2] The design team is most commonly employed by (i.e. in contract with) the property owner. Under this system, once the design is completed by the design team, a number of construction companies or construction management companies may then be asked to make a bid for the work, either based directly on the design, or on the basis of drawings and a bill of quantities provided by a quantity surveyor. Following evaluation of bids, the owner will typically award a contract to the lowest responsible bidder.
The modern trend in design is toward integration of previously separated specialties, especially among large firms. In the past, architects, interior designers, engineers, developers, construction managers, and general contractors were more likely to be entirely separate companies, even in the larger firms. Presently, a firm that is nominally an "architecture" or "construction management" firm may have experts from all related fields as employees, or to have an associated company that provides each necessary skill. Thus, each such firm may offer itself as "one-stop shopping" for a construction project, from beginning to end. This is designated as a "design Build" contract where the contractor is given a performance specification, and must undertake the project from design to construction, while adhering to the performance specifications.
Construction of a pre-fab house
Several project structures can assist the owner in this integration, including design-build, partnering, and construction management. In general, each of these project structures allows the owner to integrate the services of architects, interior designers, engineers, and constructors throughout design and construction. In response, many companies are growing beyond traditional offerings of design or construction services alone, and are placing more emphasis on establishing relationships with other necessary participants through the design-build process.
The increasing complexity of construction projects creates the need for design professionals trained in all phases of the project's life-cycle and develop an appreciation of the building as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. Building engineering is an emerging discipline that attempts to meet this new challenge.
Financial advisors
Many construction projects suffer from preventable financial problems. Underbids ask for too little money to complete the project. Cash flow problems exist when the present amount of funding cannot cover the current costs for labour and materials, and because they are a matter of having sufficient funds at a specific time, can arise even when the overall total is enough. Fraud is a problem in many fields, but is notoriously prevalent in the construction field. Financial planning for the project is intended to ensure that a solid plan, with adequate safeguards and contingency plans, is in place before the project is started, and is required to ensure that the plan is properly executed over the life of the project.
Mortgage bankers, accountants, and cost engineers are likely participants in creating an overall plan for the financial management of the building construction project. The presence of the mortgage banker is highly likely even in relatively small projects, since the owner's equity in the property is the most obvious source of funding for a building project. Accountants act to study the expected monetary flow over the life of the project, and to monitor the payouts throughout the process. Cost engineers apply expertise to relate the work and materials involved to a proper valuation. Cost overruns with government projects have occurred when the contractor was able to identify change orders or changes in the project resulting in large increases in cost, which are not subject to competition by other firm as they have already been eliminated from consideration after the initial bid.[3]
Large projects can involve highly complex financial plans. As portions of a project are completed, they may be sold, supplanting one lender or owner for another, while the logistical requirements of having the right trades and materials available for each stage of the building construction project carries forward. In many English speaking countries, but not the United States, projects typically use quantity surveyors.
Legal considerations This section does not cite any references or sources. (October 2006)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.
A construction project must fit into the legal framework governing the property. These include governmental regulations on the use of property, and obligations that are created in the process of construction.
The project must adhere to zoning and building code requirements. Constructing a project that fails to adhere to codes will not benefit the owner. Some legal requirements come from malum in se considerations, or the desire to prevent things that are indisputably bad - bridge collapses or explosions. Other legal requirements come from malum prohibitum considerations, or things that are a matter of custom or expectation, such as isolating businesses to a business district and residences to a residential district. An attorney may seek changes or exemptions in the law governing the land where the building will be built, either by arguing that a rule is inapplicable (the bridge design won't collapse), or that the custom is no longer needed (acceptance of live-work spaces has grown in the community).
A construction project is a complex net of contracts and other legal obligations, each of which must be carefully considered. A contract is the exchange of a set of obligations between two or more parties, but it is not so simple a matter as trying to get the other side to agree to as much as possible in exchange for as little as possible. The time element in construction means that a delay costs money, and in cases of bottlenecks, the delay can be extremely expensive. Thus, the contracts must be designed to ensure that each side is capable of performing the obligations set out. Contracts that set out clear expectations and clear paths to accomplishing those expectations are far more likely to result in the project flowing smoothly, whereas poorly drafted contracts lead to confusion and collapse.
Legal advisors in the beginning of a construction project seek to identify ambiguities and other potential sources of trouble in the contract structure, and to present options for preventing problems. Throughout the process of the project, they work to avoid and resolve conflicts that arise. In each case, the lawyer facilitates an exchange of obligations that matches the reality of the project.
Interaction of expertise
Design, finance, and legal aspects overlap and interrelate. The design must be not only structurally sound and appropriate for the use and location, but must also be financially possible to build, and legal to use. The financial structure must accommodate the need for building the design provided, and must pay amounts that are legally owed. The legal structure must integrate the design into the surrounding legal framework, and enforces the financial consequences of the construction process.
The first buildings were huts and shelters, constructed by hand or with simple tools. As cities grew during the bronze age, a class of professional craftsmen like bricklayers and carpenters appeared. Occasionally, slaves were used for construction work. In the middle ages, these were organized into guilds. In the 19th century, steam-powered machinery appeared, and later diesel- and electric powered vehicles such as cranes, excavators and bulldozers.
See also: History of architecture
Foundation_Engineering
Foundation
Shallow foundations of a house versus the deep foundations of a Skyscraper.
A foundation is a structure that transfers loads to the ground. Foundations are generally broken into two categories: shallow foundations and deep foundations.Contents [hide]
1 Shallow foundations
2 Deep foundations
3 Design
4 See also
Shallow foundations
Main article: Shallow foundation
Shallow foundations are usually embedded a meter or so into soil. One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. Another common type is the slab-on-grade foundation where the weight of the building is transferred to the soil through a concrete slab placed at the surface.
Deep foundations
Main article: Deep foundation
Deep foundations are used to transfer a load from a structure through an upper weak layer of soil to a stronger deeper layer of soil. There are different types of deep foundations including piles, drilled shafts, caissons, piers, and earth stabilized columns. The naming conventions for different types of foundations vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete. Sometimes these foundations penetrate bedrock.
Design
Foundations are designed to have an adequate load capacity with limited settlement by a geotechnical engineer, and the foundation itself is designed structurally by a structural engineer.
The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement is normally considered. Differential settlement is when one part of a foundation settles more than another part. This can cause problems to the structure the foundation is supporting. It is necessary that a foundation is not loaded beyond its bearing capacity or the foundation will "fail".
Other design considerations include scour and frost heave. Scour is when flowing water removes supporting soil from around a foundation (like a pier supporting a bridge over a river). Frost heave occurs when water in the ground freezes to form ice lenses.
Changes in soil moisture can cause expansive clay to swell and shrink. This swelling can vary across the footing due to seasonal changes or the effects of vegetation removing moisture. The variation in swell can cause the soil to distort, cracking the structure over it. This is a particular problem for house footings in semi-arid climates such as South Australia, Southwestern US, Turkey, Israel, Iran and South Africa where wet winters are followed by hot dry summers. Raft slabs with inherent stiffness have been developed in Australia with capabilities to resist this movement.
When structures are built in areas of permafrost, special consideration must be given to the thermal effect the structure will have on the permafrost. Generally, the structure is designed in a way that tries to prevent the permafrost from melting.
[edit]
See also
Shallow foundation
From Wikipedia, the free encyclopedia
A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. Shallow foundations include spread footing foundations, mat-slab foundations, and slab-on-grade foundationsContents [hide]
1 Spread footing foundation
2 Mat-slab foundations
3 Slab-on-grade foundation
4 See also
Spread footing foundation
In ground reinforced concrete foundation in cyclonic area, Northern Australia.
Spread footing foundations consists of strips or pads of concrete (or other materials) which transfer the loads from walls and columns to the soil or bedrock. Embedment of spread footings is controlled by several factors, including development of lateral capacity, penetration of soft near-surface layers, and penetration through near-surface layers likely to change volume due to frost heave or shrink-swell.
These foundations are common in residential construction that includes a basement, and in many commercial structures.
Mat-slab foundations
Mat-slab foundations are used to distribute heavy column and wall loads across the entire building area, to lower the contact pressure compared to conventional spread footings. Mat-slab foundations can be constructed near the ground surface, or at the bottom of basements. In high-rise buildings, mat-slab foundations can be several meters thick, with extensive reinforcing to ensure relatively uniform load transfer.
Slab-on-grade foundation
Example of slab on grade foundation
Raft slab house foundation in cyclonic area, Northern Australia.
Raft slab house foundation in cyclonic area, Northern Australia.
Slab-on-grade foundations are a structural engineering practice whereby the concrete slab that is to serve as the foundation for the structure is formed from a mold set into the ground. The concrete is then poured into the mold, leaving no space between the ground and the structure. This type of construction is most often seen in warmer climates, where ground freezing and thawing is less of a concern and where there is no need for heat ducting underneath the floor.
The advantages of the slab technique are that it is relatively cheap and sturdy, and is considered less vulnerable to termite infestation because there are no hollow spaces or wood channels leading from the ground to the structure (assuming wood siding, etc., is not carried all the way to the ground on the outer walls).
The disadvantages are the lack of access from below for utility lines, the potential for large heat losses where ground temperatures fall significantly below the interior temperature, and a very low elevation that may expose the building to flood damage in even moderate rains. Remodeling or extending such a structure may also be more difficult. Over the long term, ground settling (or subsidence) may be a problem, as a slab foundation cannot be readily jacked up to compensate; proper soil compaction prior to pour can minimize this. The slab can be decoupled from ground temperatures by insulation, with the concrete poured directly over insulation (for example, Styrofoam panels), or heating provisions (such as hydronic heating) can be built into the slab (an expensive installation, with associated running expenses).
Slab-on-grade foundations are commonly used in areas with expansive clay soil, particularly in California and Texas. While elevated structural slabs actually perform better on expansive clays, it is generally accepted by the engineering community that slab-on-grade foundations offer the greatest cost-to-performance ratio for tract and semi-custom homes. Elevated structural slabs are generally only found on large custom homes or homes with basements.
Care must be taken with the provision of services through the slab. Copper piping, commonly used to carry natural gas and water, reacts with concrete over a long period, slowly degrading until the pipe fails. Copper pipes must be lagged, run through a conduit, or plumbed into the building above the slab. Electrical conduits through the slab need to be water-tight, as they extend below ground level and can potentially expose the wiring to groundwater.
Deep foundation
A deep foundation installation for a bridge in Napa, California.
A deep foundation is a type of foundation. Deep foundations are distinguished from shallow foundations by the depth they are embedded into the ground. There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints (like property lines). There are different terms used to describe different types of deep foundations including piles, drilled shafts, caissons, and piers. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete and pre-tensioned concrete. Deep foundations can be installed by either driving them into the ground or drilling a shaft and filling it with concrete, mass or reinforced.
Pile driving operations in the Port of Tampa, FloridaContents [hide]
1 Driven foundations
1.1 Pile foundation systems
2 Drilled piles
2.1 Underreamed piles
2.2 Auger cast pile
2.3 Pier and grade beam foundation
3 Specialty piles
3.1 Micropiles
3.2 Tripod piles
3.3 Sheet piles
3.4 Soldier piles
4 Piled walls
5 Materials
5.1 Timber
5.2 Pipe piles
5.3 Prestressed concrete piles
6 See also
7 Notes
8 References
9 External links
Driven foundations
Pipe piles being driven into the ground.
Prefabricated piles are driven into the ground using a pile driver. Driven piles are either wood, concrete, or steel. Wooden piles are made from trunks of tall trees. Concrete piles are available in square, octagonal, and round cross-sections. They are reinforced with rebar and are often prestressed. Steel piles are either pipe piles or some sort of beam section (like an H-pile). Historically, wood piles were spliced together when the design length was too large for a single pile; today, splicing is only common with steel piles, though concrete piles can be spliced with difficulty. Driving piles, as opposed to drilling shafts, is advantageous because the soil displaced by driving the piles compresses the surrounding soil, causing greater friction against the sides of the piles, thus increasing their load-bearing capacity.
Pile foundation systems
Foundations relying on driven piles often have groups of piles connected by a pile cap (a large concrete block into which the heads of the piles are embedded) to distribute loads which are larger than one pile can bear. Pile caps and isolated piles are typically connected with grade beams to tie the foundation elements together; lighter structural elements bear on the grade beams while heavier elements bear directly on the pile cap.
Drilled piles
A pile machine in Amsterdam
Also called drilled piers or Cast-in-drilled-hole piles (CIDH piles).
Rotary boring techniques offer larger diameter piles than any other piling method and permit pile construction through particularly dense or hard strata. Construction methods depend on the geology of the site. In particular, whether boring is to be undertaken in 'dry' ground conditions or through water-logged but stable strata - i.e. 'wet boring'.
'Dry' boring methods employ the use of a temporary casing to seal the pile bore through water-bearing or unstable strata overlying suitable stable material. Upon reaching the design depth, a reinforcing cage is introduced, concrete is poured in the bore and brought up to the required level. The casing can be withdrawn or left in situ.
'Wet' boring also employs a temporary casing through unstable ground and is used when the pile bore cannot be sealed against water ingress. Boring is then undertaken using a digging bucket to drill through the underlying soils to design depth. The reinforcing cage is lowered into the bore and concrete is placed by tremmie pipe, following which, extraction of the temporary casing takes place.
In some cases there may be a need to employ drilling fluids (such as bentonite suspension) in order to maintain a stable shaft. Rotary auger piles are available in diameters from 350 mm to 2400 mm and using these techniques, pile lengths of beyond 50 metres can be achieved.
Underreamed piles
Underream piles have mechanically formed enlarged bases that have been as much as 6 m in diameter. The form is that of an inverted cone and can only be formed in stable soils. In such conditions they allow very high load bearing capacities.
Auger cast pile
An auger cast pile, often known as a CFA pile, is formed by drilling into the ground with a hollow stemmed continuous flight auger to the required depth or degree of resistance. No casing is required. A high slump concrete mix is then pumped down the stem of the auger. While the concrete is pumped, the auger is slowly withdrawn, lifting the spoil on the flights. A shaft of fluid concrete is formed to ground level. Reinforcement placed by hand is normally limited to 6 metres in depth. Longer reinforcement cages can be installed by a vibrator, or placed prior to pouring concrete if appropriate specialized drilling equipment is used.
Auger cast piles cause minimal disturbance, and are often used for noise and environmentally sensitive sites. Auger cast piles are not generally suited for use in contaminated soils, due to expensive waste disposal costs. In ground containing obstructions or cobbles and boulders, auger-cast piles are less suitable as damage can occur to the auger.
Pier and grade beam foundation
In most drilled pier foundations, the piers are connected with grade beams - concrete beams at grade (also referred to as 'ground' beams) - and the structure is constructed to bear on the grade beams, sometimes with heavy column loads bearing directly on the piers. In some residential construction, the piers are extended above the ground level and wood beams bearing on the piers are used to support the structure. This type of foundation results in a crawl space underneath the building in which wiring and duct work can be laid during construction or remodeling.
Specialty piles
A micropile installation
Micropiles
Micropiles, also called mini piles, are used for underpinning. Micropiles are normally made of steel with diameters of 60 to 200 mm. Installation of micropiles can be achieved using drilling, impact driving, jacking, vibrating or screwing machinery.[1]
Where the demands of the job require piles in low headroom or otherwise restricted areas and for specialty or smaller scale projects, micropiles can be ideal. Micropiles are often grouted as shaft bearing piles but non-grouted micropiles are also common as end-bearing piles.
Tripod piles
The use of a tripod rig to install piles is one of the more traditional ways of forming piles, and although unit costs are generally higher than with most other forms of piling, it has several advantages which have ensured its continued use through to the present day. The tripod system is easy and inexpensive to bring to site, making it ideal for jobs with a small number of piles. It can work in restricted sites (particularly where height limits exist), it is reliable, and it is usable in almost all ground conditions.
Sheet piles
Sheet piling is a form of driven piling using thin interlocking sheets of steel to obtain a continuous barrier in the ground. The main application of steel sheet piles is in retaining walls and cofferdams erected to enable permanent works to proceed.
Soldier piles
A soldier pile wall using reclaimed railway sleepers as lagging
Soldier piles, also known as king piles or Berlin walls, are constructed of wide flange steel H sections spaced about 2 to 3 m apart and are driven prior to excavation. As the excavation proceeds, horizontal timber sheeting (lagging) is inserted behind the H pile flanges.
The horizontal earth pressures are concentrated on the soldier piles because of their relative rigidity compared to the lagging. Soil movement and subsidence is minimized by maintaining the lagging in firm contact with the soil.
Soldier piles are most suitable in conditions where well constructed walls will not result in subsidence such as over-consolidated clays, soils above the water table if they have some cohesion, and free draining soils which can be effectively dewatered, like sands.
Unsuitable soils include soft clays and weak running soils that allow large movements such as loose sands. It is also not possible to extend the wall beyond the bottom of the excavation and dewatering is often required.
Piled walls
Sheet piling, by a bridge, was used to block a canal in New Orleans after Hurricane Katrina damaged it.
These methods of retaining wall construction employ bored piling techniques - normally CFA or rotary. They provide special advantages where available working space dictates that basement excavation faces be vertical. Both methods offer technically effective and cost efficient temporary or permanent means of retaining the sides of bulk excavations even in water bearing strata.
When used in permanent works, these walls can be designed to accommodate vertical loads in addition to moments and horizontal forces.
Construction of both methods is the same as for foundation bearing piles. Contiguous walls are constructed with small gaps between adjacent piles. The size of this space is determined by the nature of the soils.
Secant piled walls are constructed such that space is left between alternate 'female' piles for the subsequent construction of 'male' piles. Construction of 'male' piles involves boring through the concrete in the 'female' piles in order to key 'male' piles between them. The male pile is the one where steel reinforcement cages are installed, though in some cases the female piles are also reinforced.
Secant piled walls can either be true hard/hard, hard/intermediate (firm), or hard/soft, depending on design requirements. Hard refers to structural concrete and firm or soft is usually a weaker grout mix containing bentonite.
All types of wall can be constructed as free standing cantilevers, or may be propped if space and sub-structure design permit. Where party wall agreements allow, ground anchors can be used as tie backs.
Materials
Timber
As the name implies, timber piles are piles made of timber. Historically, timber has been a plentiful, locally-available resource in many areas of the globe. Today, timber piles are still more affordable than concrete or steel. Compared to other types of piles (steel or concrete), timber piles are not suitable for heavier loads. A main consideration regarding timber piles is that they should be protected from deterioration above groundwater level. Timber will last for a long time below the groundwater level. For timber to deteriorate, two elements are needed: water and oxygen. Below the groundwater level, oxygen is lacking even though there is ample water. Hence, timber tends to last for a long time below groundwater level. It has been reported that some timber piles used during 16th century in Venice still survive since they were below groundwater level. Timber can be treated with paints and various other techniques to protect from boring insects. One of the main disadvantages of timber piles is the difficulty in splicing. Splicing is the process of joining two piles to make a longer pile. Unlike steel and concrete piles, splicing is a difficult process with timber piles.
Pipe piles
Pipe piles are a type of steel driven pile foundation and are a good candidate for battered piles.
Pipe piles can be driven either open end or closed end. When driven open end, soil is allowed to enter the bottom of the pipe or tube. If an empty pipe is required, a jet of water or an auger can be used to remove the soil inside following driving. Closed end pipe piles are constructed by covering the bottom of the pile with a steel plate or cast steel shoe.
In some cases, pipe piles are filled with concrete to provide additional moment capacity or corrosion resistance. In the United Kingdom, this is generally not done in order to reduce the cost. In these cases, corrosion protection is provided by allowing for a sacrificial thickness of steel or by adopting a higher grade of steel. If a concrete filled pipe pile is corroded, most of the load carrying capacity of the pile will remain intact due to the concrete, while it will be lost in an empty pipe pile.
The structural capacity of pipe piles is primarily calculated based on steel strength and concrete strength if filled. The thickness of the steel should be reduced to account for corrosion, typically by 1/16 in.
The amount of corrosion for a steel pipe pile can be categorized; for a pile embedded in a non aggressive and natural soil, 0.015 mm per side per year can be assumed from the British Steel Piling Handbook. Eurocode 3 now specifies various corrosion rates based on the nature or soil conditions and pipe pile exposure.
Steel pipe piles can either be new steel manufactured specifically for the piling industry or reclaimed steel tubular casing previously used for other purposes such as oil and gas exploration.
Prestressed concrete piles
Concrete piles are typically made with steel reinforcing and prestressing tendons to obtain the tensile strength required to survive handling and driving, and to provide sufficient bending resistance.
Long piles can be difficult to handle and transport. Pile joints can be used to join two or more short piles to form one long pile. Pile joints can be used with both precast and prestressed concrete piles.
Mekanika Rekayasa
Mekanika rekayasa???
Mekanika teknik atau dikenal juga sebagai mekanika rekayasa atau analisa struktur merupakan bidang ilmu utama yang dipelajari di ilmu teknik sipil. Pokok utama dari ilmu tersebut adalah mempelajari perilaku struktur terhadap beban yang bekerja padanya. Perilaku struktur tersebut umumnya adalah lendutan dan gaya-gaya (gaya reaksi dan gaya internal).
Dalam mempelajari perilaku struktur maka hal-hal yang banyak dibicarakan adalah
- Stabilitas
- keseimbangan gaya
- kompatibilitas antara deformasi dan jenis tumpuannnya elastisitas
Dengan mengetahui gaya-gaya dan lendutan yang terjadi maka selanjutnya struktur tersebut dapat direncanakan atau diproporsikan dimensinya berdasarkan material yang digunakan sehingga aman dan nyaman (lendutannya tidak berlebihan) dalam menerima beban tersebut.
Gaya luar adalah muatan dan reaksi yang menciptakan kestabilan atau keseimbangan konstruksi. Muatan yang membebani suatu kontruksi akan dirambatkan oleh kontruksi ke dalam tanah melalui pondasi. Gaya-gaya dari tanah yang memberikan perlawanan terhadap gaya rambat tersebut dinamakan reaksi.
Apa itu Muatan?
Muatan adalah beban yang membebani suatu konstruksi baik berupa berat kendaraan, kekuatan angin, dan berat angin.
Muatan-muatan tersebut mempunyai besaran, arah, dan garis kerja, misalnya:
- Angin bekerja tegak lurus bidang yang menentangnya, dan diperhitungkan misalnya 40 kN/m2, arahnya umum mendatar.
- Berat kendaraan, merupakan muatan titik yang mempunyai arh gaya tegak lurus bidang singgung roda, dengan besaran misalnya 5 tN.
- Daya air, bekerja tegak lurus dinding di mana ada air, besarnya daya air dihitung secara hidrostatis, makin dalam makin besar dayanya.
Berdasarkan pengertian tersebut muatan-muatan dapat dibedakan atas beberapa kelompok menurut cara kerjanya.
1. Ada muatan yang bekerjanya sementara dan ada pula yang terus-menerus (permanen). Mutan yang dimaksud adalah:
1.1. Muatan mati, yaitu muatan tetap pada konstruksi yang tidak dapat dipindahkan atau tidak habis. Misalnya:
Ø Berat sendiri konstruksi beton misalnya 2200 kN/m3 , dan
Ø Berat tegel pada pelat lantai misalnya 72 kN/m2.
2. Ada muatan yang garis kerjanya dianggap suatu titik, ada yang tersebar. Muatan yang dimaksud adalah:
2.1. Muatan titik atau muatan terpusat. Yaitu muatan yang garis kerjanya dianggap bekerja melalui satu titik, misalnya:
Ø Berat seseorang melalui kaki misalnya 60 kN dan
Ø Berat kolom pada pondasi misalnya 5000 kN;
Muatan terbagi ini dapat dijabarkan sebagai berikut:
Ø Muatan terbagi rata, yaitu muatan terbagi yang dianggap sama pada setiap satuan luas.
Ø Muatan terbagi tidak rata teratur, yaitu muatan yang terbagi tidak sama berat untuk setiap satuan luas.
3. Muatan momen, yaitu muatan momen akibat dari muatan titik pada konstruksi sandaran. Gaya horizontal pada sandaran menyebabkan momen pada balok.
4. Muatan puntir, suatu gaya nonkoplanar mungkin bekerja pada suatu balok sehingga menimbulkan suatu muatan puntir, namun masih pada batas struktur statik tertentu.
5. Dalam kehiduypan sehari-hari sering dijumpai muatan yang bekerjanya tidak langsung pada konstruksi, seperti penutup atap ditumpu oleh gording dan tidak langsung pada kuda-kuda.
Ø Muatan langsung, Orang yang berdiri pada titian suatu jembatan akan bekerja secara langsung langsung pada titian jembatan tersebut.
Ø Muatan taklangsung, berat seseorang yang berdiri pada lantai suatu jembatan akan bekerja tidak langsung pada konstruksi jembatan. Berat seseorang tersebut dipindahkan lewat lantai, anak balok baru dipindahkan lagi kepada balok induk konstruksi jembatannya.
Apa itu perletakan?
Perletakan adalah suatu konstruksi direncanakan untuk suatau keperluan tertentu.
Tugas utama suatu konstruksi adalah mengumpulkan gaya akibat muatan yang bekerja padanya dan meneruskannya ke bumi. Untuk melaksanakan tugasnya dengan baik maka konstruksi harus berdiri dengan kokoh. Rosenthal menyatakan bahwa semua beban diteruskan ke bumi melalui sesingkat-singkatnya.
Kondisi yang harus dipertimbangkan?
Pertama yang harus dipertimbangkan adalah stabilitas konstruksi. Suatu konstruksi akan stabil bila konstruksi diletakkan di atas pondasi yang baik. Pondasi akan melawan gaya aksi yang diakibatkan oleh muatan yang diteruskan oleh konstruksi kepada pondasi. Gaya lawan yang ditimbulkan pada pondasi disebut: Reaksi. Dalam kasus ini pondasi digambarkan sebagai perletakan. Berikut ini diuraikan tiga jenis perletakan yang merupakan jenis perletakan yang umum digunakan. Yaitu perletakan yang dapat menahan momen, gaya vertikal dan gaya horizontal.dan ada maca-macam perletakan yang perlu dipahami yaitu:
Ø Perletakan sendi, yaitu perletakan terdiri dari poros dan lubang sendi. Pada perletakan demikian dianggap sendinya licin sempurna, sehingga gaya singgung antara poros dan sendi tetap normal terhadap bidang singgung, dan arah gaya ini akan melalui pusat poros.
Ø Perletakan geser, yaitu perletakan yang selalu memiliki lubang sendi. Apabila poros ini licin sempurna maka poros ini hanya dapat meneruskan gaya yang tegak lurus bidang singgung di mana poros ini diletakkan.
Ø Perletakan pendel, yaitu suatu perletakan yang titik tangkap dan garis kerjanya diketahui.
Ø Perletakan jepit, perletakan ini seolah-olah dibuat dari balok yang ditanamkan pada perletakannya, demikian sehingga mampu menahan gaya-gaya maupun momen dan bahkan dapat menahan torsi.
Gaya dalam adalah gaya rambat yang diimbangi oleh gaya yang berasal dari bahan konstruksi, berupa gaya lawan, dari konstruksi.
Analisis hitungan gaya dalam dan urutan hitungan ini dapat diuraikan secara singkat sebagai berikut:
1. Menetapkan dan menyederhanakan konstruksi menjadi suatu sistem yang memenuhi syarat yang diminta.
2. Menetapkan muatan yang bekerja pada konstruksi ini.
3. Menghitung keseimbangan luar.
4. Menghitung keseimbangan dalam.
5. Memeriksa kembali semua hitungan.
Dengan syarat demikian konstruksi yang dibahas akan digambarkan sebagai suatu garis sesuai dengan sumbu konstruksi, yang selanjutnya disebut: Struktur
Hubungan antara muatan, gaya lintang, dan momen...
Untuk membahas pertanyaan tersebut, harus mempelajari suatu struktur sederhana yang dibebani muatan penuh terbagi rata.
Gaya dalam di m dapat dihitung sebesar:
Mm = Va.x – ½ qx2 =
½ qlx – ½ qx2...................(1.1)
Lm = ½ ql – qx............................(1.2)
Gaya dalam di n dapat dihitung sebesar:
Mn = Va (x + dx) – 1/2q (x + dx)2............(1.4)
Ln = ½ qL – q (x + dx)............................(1.5)
Persamaan (1.4) dan (1.5) tersebut dapat ditulis
Pula sebagai:
Mn = Mm + dM =
Mm + Lm.dx – q.dx.1/2 dx..............(1.6)
Ln = Lm + dL = Lm – q.dx........................(1.7)
Persamaan tersebut setelah diselesaikan didapat:
dM/dx = Lx..............................................(1.8)
dL/dx = - q...............................................(1.9)
Kiranya perlu ditambahkan bahwa perubahan nilai beban ditiap titik adalah tetap, yang berarti dq/dx = 0
Dengan demikian memang terbukti adanya hubungan antara muatan, gaya lintang dan momen. Hubungan itu tampak pula pada persamaan-persamaan di atas, yaitu: gaya lintang merupakan fungsi turunan dari momen , dan beban merupakan fungsi turunan dari gaya lintang, atau sebaliknya gaya lintang merupakan jumlah integrasi dari beban, dan momen merupakan jumlah integrasi dari gaya lintang.
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