Video from my YouTube channel

Subscribe to My You tube channel

span-by-span method of bridge construction

By -
precast segmental bridge construction can effectively reduce the time of bridge construction, reducing the time of construction mean minimizing the disturb to road commuter and neighbors, also increase the quality of constructed bridge, the reason for the increase in bridge quality is due to high-quality controls in factories that produce precast segments. on the other hand, this type of construction required skilled workmanship and special equipment not available for certain regions.

Figure 1








Precast segmental bridges may be erected with four construction methods: span-by-span erection with self-launching gantry; balanced cantilever erection with ground cranes, lifting frames or self-launching gantry; progressive placement with a cable-stayed system or temporary piers; and incremental launching. The development of external post-tensioning contributes to the increase of using the span-by-span construction method. this method is cost-effective, rapid construction method and can be used for long bridges (25 to 45 m) with large plan radius. 
Figure 2

Deck constructed starts at abutment towards the piers. segments placed at the end of each other until one span is completed. segments will be placed and held in the correct location using temporary staying mast system or more commonly assembly truss. before beginning with launching and placing of segments, assembly truss will be braced to piers. then segments will be placed in the correct location using sliding bads, expoy will use to close and joint segments.

after the completion of placing all the segments for one slab, post-tensioning tendons are placed inside ducts and the whole span will be stressed.







Comments

  1. On The Move TransportNovember 7, 2020 at 1:01 PM

    I felt very happy while reading this article. we provide brisbane crane trucks at affordable cost. to know more visit our website.

    ReplyDelete
  2. Cricket Machinery LLCMay 24, 2021 at 11:06 PM

    Remarkable post. I simply came across your blog and desired to say that I have really enjoyed searching your blog posts. Thank you for sharing such blogs. Rent Bidwell bridge paving machinery in USA

    ReplyDelete

Post a Comment

Videos from My Youtube channel

Popular posts from this blog

Binding wire for steel reinforcement

By -
Image
  Binding wires are used to tie steel bars together. These wires are playing a significant role in maintaining the reinforcement stability and rigidity. Wires are used to tie the steel bars at intersections points. By tying the steel bars together, we ensure that the steel bars will not move from their locations during construction or during the time of concreting. In slabs, binding wires are used to tie longitudinal and transverse bars together. In columns, it is used to tie vertical bars with stirrups.   Figure 1 There are various types of binding wires such as  Black annealed baling wire, Stainless Steel Binding Wire, and PVC coated binding wires.  Black annealed baling wire used to tie black steel. The popular size for black wire ranges from 16 to 22 gauges. Stainless steel binding wires are used to bind stainless steel reinforcement. Stainless steel reinforcement is used in a harsh environment where the black steel gets rusted quickly. Therefore, stainless ...
Read more

Pile cap

By -
Image
Pile cap used to transfer the loads from superstructure to the piling. The pile cap is thick concrete mat rests on piles. It is part of the foundation and used to distribute the loads over the piles. Piles used when the soil bearing is not enough to carry loads of the structure. Figure 1  construction management: concrete construction bridge construction:How to become a bridge engineer Pile cap construction procedure Excavation around piles: After 7 days of the casting of the pile the concrete will gain approximately, 70% of it is compressive strength. The soil around piles will be removed to the required levels and dimension that allows construction of the pile cap. A step shall be made if the excavation is more than 1.5 m to prevent soil collapse. Figure 2 Pile head cutting: Concrete will be removed up to cut off level. If concrete under the cut off level is unsound. It shall be removed, and the pile will be repaired...
Read more

Bridge Diaphragm

By -
Image
The main function of diaphragms is to provide a stiffening effect to deck slab in case bridge webs are not situated directly on top of bearings. Therefore, diaphragms may not be necessary in case bridge bearings are placed directly under the webs because loads in bridge decks can be directly transferred to the bearings.On the other hand, diaphragms also help to improve the load-sharing characteristics of bridges. Diaphragms also contribute to the provision of torsional restraint to the bridge deck. Diaphragm will be used also to resist stresses that occurs during the post-tensioning process. Post-tensioning hardware are casted inside the diaphragm. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer Types of diaphragm: Diaphragm at the span end: this type of diaphragms will be located between two bridge spans or at the bridge abutments. Expansion joints will be used to connect bridge spans. This ...
Read more

Chamfers for concrete structures

By -
Image
In general, the edges of concrete members are chamfered. Usually during the process of installing forms for a structural member such as pile cap, a chamfer a PVC chamfer as shown in figure no:1 installed at the edges of the structural members. These chamfers will form smooth slanted edges, as shown in figure no:2. The size of chamfers can be 20x20mm or more as shown on the contract drawing. The PVC chamfer fixed to forms by nails. We should ensure that the PVC chamfer fixed in their correct locations, and we should ensure that the PVC chamfer is straight and not moving up or down. Checking the alignment and location of PVC chamfer is important, so the chamfered concrete edge will have a good appearance after the form’s removal.  Figure 1 Figure 2 Chamfering the concrete edges done for many reasons such as aesthetics, some suggesting that the chamfering of concrete edges done for safety to reduce the damage of objects due to impact with sharp concrete edges. Actually, ...
Read more

Non-Working Pile Testing and Static Compression Load Test

By -
Image
Purpose of Non-Working Piles Non-working piles are constructed at the beginning of the project to evaluate soil bearing capacity and determine the maximum settlement. These piles are loaded up to twice the working load. Based on the test results, the pile length may be adjusted. If the measured settlement exceeds the allowable limit, the pile length will be increased accordingly. construction management: concrete construction bridge construction:How to become a bridge engineer Static Compression Load Test The static compression load test provides insight into how the pile responds to loading. Settlement is measured at different load increments to determine the appropriate pile design length. The maximum applied load is typically twice the working load (2 × working load) or as specified by local standards. The following steps outline the testing procedure: A. Steel Cage Preparation The steel reinforcement cage is prepared in accordance with the approved shop drawings. ...
Read more

stress-strain diagram for aluminium alloy and rubber

By -
Image
figure no:1 showing the stress-strain diagram for aluminum alloy. we can notice from the stress-stress diagram that aluminum has a considerable ductility. despite the absence of explicit yield point as in structural steel . the initial portion of the stress-strain curve is linear with a recognizable proportional limit. the proportional limit for aluminum alloy ranges from 70 to 410 Mpa (10 to 60 Ksi). aluminum alloy undergoes large strain before failure. ultimate stress ranges from 140 to 550 Mpa (20 to 80 Ksi). construction management: concrete construction bridge construction:How to become a bridge engineer Figure-1 Yield stress for aluminum alloy can be determined by drawing offset line parrel to the linear portion of the stress-strain curve. the straight line offset by a standard strain such as 0.002. the intersection point with the stress-strain curve is the point of yield stress. figure no:2 illustrates the concept of offset method. yield stress acquire...
Read more

Equivalent Single Axle Load (ESAL) in Pavement Design

By -
Image
In pavement engineering, determining the Equivalent Single Axle Load (ESAL) is a crucial step in designing a durable and efficient roadway. ESAL simplifies the complexity of mixed traffic loading by converting it into a single representative value, allowing engineers to assess the cumulative impact of various vehicle types on pavement performance. The Concept of ESAL Roadways are subjected to traffic from a wide range of vehicles, each with different axle configurations and weights. Since these vehicles exert varying degrees of stress on the pavement, ESAL provides a standardized measure to represent their combined effect. The core idea behind ESAL is to express the cumulative traffic load on a road pavement as an equivalent number of passes of a standard axle load. This standard axle load is typically set at 80 kN . For example, if a road is subjected to an ESAL value of 10,000,000 , it means the pavement experiences the same level of stress as 10 million passes of a single standard...
Read more

wing wall arrangement and orientation for abutments

By -
Image
wing wall main function is to retain the embankment near abutment. the common slope is 2:1. greater than 2:1 is not allowed. figure no: shows a wing wall for the abutment. Figure 1  there is three arrangement for wing wall: wing wall parallel to abutment: easy to build. construction can be done in a short time. this type of wing wall will not disturb the existing embankment and utilities but it is not the most economical arrangement.   figure 2 construction management: concrete construction bridge construction:How to become a bridge engineer wing wall at an angle with abutments: this type is most economical among the three arrangement. Figure 3 wing wall perpendicular to abutment: in this arrangement. wing wall provides a continuous alignment with bridge deck which can be used to support parapets. this arrangement will disturb existing embankment and utilities adjacent to the structure. for curve bridge, this type o...
Read more

Structural design of road pavement

By -
Image
  Designing efficient and durable roads starts with understanding one key factor: traffic. Traffic analysis provides engineers with essential data that directly influences decisions about road width, pavement thickness, and overall design. In this blog, we’ll walk through the fundamental steps of traffic analysis, from traffic surveys to axle load studies, and how each component contributes to building roads that last. watch the full course from here 1. Traffic Analysis The amount and type of traffic a road will carry play a crucial role in pavement design. Roads with heavier traffic flows require not only wider carriageways but also thicker pavements to withstand the higher load repetitions. To estimate how much load a road will bear over its design life, engineers need to conduct a traffic survey . This survey helps assess current traffic volumes and project future trends, giving us a clearer picture of what the pavement needs to endure. 1.1 Traffic Surveys: Gat...
Read more

Modular expansion joint

By -
Image
The basic concept of modular expansion joint is the divide the gap for expansion joint into smaller gaps using a separation beam, and it can accommodate a wide range of movement up to 2000 mm and it can accommodate transverse movement and rotation also. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer The modular expansion joint allows movement in every direction. It allows movement in the longitudinal and transverse direction. It can accommodate a large movement in transverse direction compared to the elastomeric joint. Also, it can rotate about an axis. It can accommodate large transverse and vertical movement without developing constraint forces. A completely watertight system with drainage at the bridge surface. Component of modular expansion joint Separation beam: this beam will span the opening, and it will rest on the support bar. Strip seal: seal shall be interlocked to separation and ed...
Read more