1、 外文文献原文The bridge crack produced the reason to simply analyse In recent years, the traffic capital construction of our province gets swift and violent development, all parts have built a large number of concrete bridges. In the course of building and using in the bridge, relevant to influence projec
2、t quality lead of common occurrence report that bridge collapse even because the crack appears The concrete can be said to often have illness coming on while fracturing and frequently-occurring disease , often perplex bridge engineers and technicians. In fact , if take certain design and constructio
3、n measure, a lot of cracks can be overcome and controlled. For strengthen understanding of concrete bridge crack further, is it prevent project from endanger larger crack to try ones best, this text make an more overall analysis , summary to concrete kind and reason of production , bridge of crack a
4、s much as possible, in order to design , construct and find out the feasible method which control the crack , get the result of taking precautions against Yu WeiRan. Concrete bridge crack kind, origin cause of formation In fact, the origin cause of formation of the concrete structure crack is compli
5、cated and various, even many kinds of factors influence each other , but every crack has its one or several kinds of main reasons produced . The kind of the concrete bridge crack, on its reason to produce, can roughly divide several kinds as follows : (1) load the crack caused Concrete in routine qu
6、iet . Is it load to move and crack that produce claim to load the crack under the times of stress bridge, summing up has direct stress cracks , two kinds stress crack onces mainly. Direct stress crack refer to outside load direct crack that stress produce that cause. The reason why the crack produce
7、s is as follows, 1, Design the stage of calculating , does not calculate or leaks and calculates partly while calculating in structure； Calculate the model is unreasonable； The structure is supposed and accorded with by strength actually by strength ； Load and calculate or leak and calculate few； In
8、ternal force and matching the mistake in computation of muscle； Safety coefficient of structure is not enough. Do not consider the possibility that construct at the time of the structural design； It is insufficient 广东工业 大学本科 毕业设计 外文翻译 第 1 页 to design the section； It is simply little and assigning th
9、e mistake for reinforcing bar to set up； Structure rigidity is insufficient； Construct and deal with improperly； The design drawing can not be explained clearly etc. 2, Construction stage, does not pile up and construct the machines , material limiting ； Is it prefabricate structure structure receiv
10、e strength characteristic , stand up , is it hang , transport , install to get up at will to understand； Construct not according to the design drawing, alter the construction order of the structure without authorization , change the structure and receive the strength mode； Do not do the tired intens
11、ity checking computations under machine vibration and wait to the structure . 3, Using stage, the heavy-duty vehicle which goes beyond the design load passes the bridge； Receive the contact , striking of the vehicle , shipping； Strong wind , heavy snow , earthquake happen , explode etc. Stress crack
12、 once means the stress of secondary caused by loading outside produces the crack. The reason why the crack produces is as follows, 1, In design outside load function , because actual working state and routine , structure of thing calculate have discrepancy or is it consider to calculate, thus cause
13、stress once to cause the structure to fracture in some position. Two is it join bridge arch foot is it is it assign X shape reinforcing bar , cut down this place way , section of size design and cut with scissors at the same time to adopt often to design to cut with scissors, theory calculate place
14、this can store curved square in , but reality should is it can resist curved still to cut with scissors, so that present the crack and cause the reinforcing bar corrosion. 2, Bridge structure is it dig trough , turn on hole , set up ox leg ,etc. to need often, difficult to use a accurate one diagram
15、matic to is it is it calculate to imitate to go on in calculating in routine, set up and receive the strength reinforcing bar in general foundation experience. Studies have shown , after being dug the hole by the strength component , it will produce the diffraction phenomenon that strength flows, in
16、tensive near the hole in a utensil, produced the enormous stress to concentrate. In long to step prestressing force of the continuous roof beam , often block the steel bunch according to the needs of section internal force in stepping, set up the anchor head, but can often see the crack in the ancho
17、r firm section adjacent place. So if deal with improper, in corner or component form sudden change office , block place to be easy to appear crack strength 广东工业 大学本科 毕业设计 外文翻译 第 2 页 reinforcing bar of structure the. In the actual project, stress crack once produced the most common reason which loads
18、 the crack. Stress crack once belong to one more piece of nature of drawing , splitting off , shearing. Stress crack once is loaded and caused, only seldom calculate according to the routine too, but with modern to calculate constant perfection of means, times of stress crack to can accomplish reaso
19、nable checking computations too. For example to such stresses 2 times of producing as prestressing force , creeping ,etc., departments finite element procedure calculates levels pole correctly now, but more difficult 40 years ago. In the design, should pay attention to avoiding structure sudden chan
20、ge (or section sudden change), when it is unable to avoid , should do part deal with , corner for instance, make round horn , sudden change office make into the gradation zone transition, is it is it mix muscle to construct to strengthen at the same time, corner mix again oblique to reinforcing bar
21、, as to large hole in a utensil can set up protecting in the perimeter at the terms of having angle steel. Load the crack characteristic in accordance with loading differently and presenting different characteristics differently. The crack appear person who draw more, the cutting area or the serious
22、 position of vibration. Must point out , is it get up cover or have along keep into short crack of direction to appear person who press, often the structure reaches the sign of bearing the weight of strength limit, it is an omen that the structure is destroyed, its reason is often that sectional siz
23、e is partial and small. Receive the strength way differently according to the structure, the crack characteristic produced is as follows: 1, The centre is drawn. The crack runs through the component cross section , the interval is equal on the whole , and is perpendicular to receiving the strength d
24、irection. While adopting the whorl reinforcing bar , lie in the second-class crack near the reinforcing bar between the cracks. 2, The centre is pressed. It is parallel on the short and dense parallel crack which receive the strength direction to appear along the component. 3, Receive curved. Most n
25、ear the large section from border is it appear and draw into direction vertical crack to begin person who draw curved square, and develop toward neutralization axle gradually. While adopting the whorl reinforcing bar , can see shorter second-class crack among the cracks. When the structure matches muscles less, there are few but wide cracks, fragility destruction may take place in the
