Site Visit (bunnings)

Looking at beams and columns

Internally, beams experience compressive, tensile and shear stresses as a result of the loads applied to them. Typically, under gravity loads, the original length of the beam is slightly reduced to enclose a smaller radius arc at the top of the beam, resulting in compression, while the same original beam length at the bottom of the beam is slightly stretched to enclose a larger radius arc, and so is under tension. The same original length of the middle of the beam, generally halfway between the top and bottom, is the same as the radial arc of bending, and so it is under neither compression nor tension, and defines the neutral axis (dotted line in the beam figure). Above the supports, the beam is exposed to shear stress. There are some reinforced concrete beams that are entirely in compression. These beams are known as prestressed concrete beams, and are fabricated to produce a compression more than the expected tension under loading conditions. High strength steel tendons are stretched while the beam is cast over them. Then, when the concrete has begun to cure, the tendons are released and the beam is immediately under eccentric axial loads. This eccentric loading creates an internal moment, and, in turn, increases the moment carrying capacity of the beam. They are commonly used on highway bridges.
The primary tool for structural analysis of beams is the Euler-Bernoulli beam equation. Other mathematical methods for determining the deflection of beams include "method of virtual work" and the "slope deflection method". Engineers are interested in determining deflections because the beam may be in direct contact with a brittle material such as glass. Beam deflections are also minimized for aesthetic reasons. A visibly sagging beam, though structurally safe, is unsightly and to be avoided. A stiffer beam (high modulus of elasticity and high second moment of area) produces less deflection. Mathematical methods for determining the beam forces (internal forces of the beam and the forces that are imposed on the beam support) include the "moment distribution method", the force or flexibility method and the matrix stiffness method.

construcction in bejing article

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Infrastructural construction in Beijing continues to increase( 2003-10-16 03:19) (China Daily)
A senior official with the Beijing Municipal Government on October 15 promised more opportunities for non-governmental capital in the city's stepped-up development of infrastructure facilities.
"We should use innovative ways to break industry barriers to attract more social funds through the market,'' Liu Yongfu, director of the Construction Commission of the Beijing Municipal Government, told the Standing Committee of the 12th Beijing Municipal People's Congress at its seventh session.
"By introducing a market competition mechanism, social funds should be allowed to be used in the construction of major municipal engineering projects through joint funding, joint operating, taking on shares, franchising, and project financing,'' Liu said.
Specifically, social funds will be welcomed in such areas as rail transport, public utilities and environmental projects.
The Beijing Municipal Government has been announcing major engineering projects each year, in order to give a substantial push to the city's infrastructure upgrades. Out of 60 such projects this year, 47 have been started construction, while the rest will be started before the end of this year, according to Liu.
As much as 32.81 billion yuan (US$3.97 billion) has been invested in these projects this year so far, roughly one third of the city's total investment on fixed assets for that period.
But were it not for financing difficulties, more projects would have been kicked off, said Liu. For example, construction of the Sixth Ring Road has been postponed to next year due to difficulties securing financing.
In particular, Liu said, the commission should pay more attention to the investment intentions of large international companies and attract more of them to get involved in the rapid economic development of Beijing through mergers, acquisitions and transfers of State-owned shares.
As far as Liu is concerned, the construction of these major engineering projects has produced obvious improvements in local investment and the city's natural environment.
One case in point, said Liu, is the completion of an afforestation project of 59,363 hectares aimed to reducing the city's sandstorms, which has helped the city enjoy 161 days of good air quality by September 15 this year, 62.6 per cent of the total number of days so far. Beijing's overall target for this year is 60 per cent.
Also at yesterday's session, the standing committee urged the municipal government to adopt effective measures to attract more investment from Taiwan as well.
Although the city has published various practical measures to ensure its appeal to Taiwan investors, Overseas Chinese Affairs Standing Committee Director Chen Xingbo said Beijing still needs better monitoring mechanisms to safeguard the legitimate rights of Taiwanese investors and their families.
By the end of July, Taiwanese investors had established 1,911 enterprises in the city, with a total contractual investment of US$1.41 billion.


from http://www.chinadaily.com.cn/en/doc/2003-10/16/content_272413.htm
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I found this arcticle very interesting in discussing how and why beijing is become such a growing country due to its extremely rapid growth in construction.

Steel construction

Steel construction and the industry
Because of the critical role played by steel in infrastructural and overall economic development, the steel industry is often considered to be an indicator of economic progress.
The economic boom in China and India has caused a massive increase in the demand for steel in recent years. Between 2000 and 2005, world steel demand increased by 6%. Since 2000, several Indian and Chinese steel firms have risen to prominence like Tata Steel (which bought Corus Group in 2007), Shanghai Baosteel Group Corporation and Shagang Group. ArcelorMittal is however the world's largest steel producer.
The British Geological Survey reports that in 2005, China was the top producer of steel with about one-third world share followed by Japan, Russia and the USA.
In 2008, steel will be traded as a commodity in the London Metal Exchange.

Uses of Steel
Iron and steel are used widely in the construction of roads, railways, infrastructure and buildings. Most large modern structures, such as stadiums and skyscrapers, bridges and airports, are supported by a steel skeleton. Even those with a concrete structure will employ steel for reinforcing. In addition to widespread use in major appliances and cars (despite growth in usage of aluminium, it is still the main material for car bodies), steel is used in a variety of other construction-related applications, such as bolts, nails, and screws.

week 6

Week 5

This diagram shows a basic section of wall to concrete panel again labeled with the key components

Week 4

This week we looked at concrete construction in detail. In particularly learning about the two main categories; Pre-cast and tilt up.

Second SIte visit

Reinforced concrete is concrete in which reinforcement bars ("rebars") or fibers have been incorporated to strengthen a material that would otherwise be brittle. In industrialised countries, nearly all concrete used in construction is reinforced concrete.

Concrete is reinforced to give it extra tensile strength; without reinforcement, many concrete buildings would not have been possible.Reinforced concrete can encompass many types of structures and components, including slabs, walls, beams, columns, foundations, frames and more.Reinforced concrete can be classified as precast concrete and cast in-situ concrete.Much of the focus on reinforcing concrete is placed on floor systems. Designing and implementing the most efficient floor system is key to creating optimal building structures. Small changes in the design of a floor system can have significant impact on material costs, construction schedule, ultimate strength, operating costs, occupancy levels and end use of a building.

Week 3

This diagram shows a typical portal frame. The Lecturer heavily focused on the joining options for U breams, looking at booth rigid connections and flexible connections and the load and axial load properties of each.