Video from my YouTube channel

Subscribe to My You tube channel

Case study: Widening an existing bridge structure Challenges and solutions

By -

Publish your paper from here

This paper is a study that summarizes, the procedure used to increase the capacity of an existing concrete bridge in the UAE. Traffic congestion is a severe problem in modern life. Severe congestion can negatively impact the country's economy, environment, and the health of road commuters. The increase in trip duration due to traffic congestion will result in consuming more fuel which results in a higher cost of trip and more emissions which affect both the economy and the environment. Moreover, the road commuter will be traveling for a long time which can affect their sleeping hours and mental health. Constructing more roads, and bridges and encouraging people to use public transport are some of the measures taken to reduce traffic congestion. To evaluate the effectiveness of an existing highway, certain parameters such as traffic quantity, type of vehicles in the traffic stream, speed of traffic stream, and the density of traffic stream will be measured and assessed to determine the need for increasing the road capacity. This paper considers the structural part and challenges faced during the process of widening an existing bridge structure. The existing bridge under consideration is composed of two spans with a length of 33.10 m of each span, two abutments with pot bearing connection, a single monolithic pier, asphaltic plug expansion joint at abutments, voided post-tensioned concrete slab with concrete barriers. The decision was taken to widen the existing bridge to relieve the aggravated traffic jam problem. The development of residential areas nearby resulted in increasing the volume of traffic exceeding the existing road capacity. The new development proposal involves the construction of a completely new bridge with 4 lanes and the widening of the existing bridge. The final output is two bridges with 4 lanes in each direction

Read more from:

https://www.researchgate.net/publication/377951645_Case_study_Widening_an_existing_bridge_structure_Challenges_and_solutions




Comments

Post a Comment

Videos from My Youtube channel

Popular posts from this blog

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

Casing for piles

By -
Image
The casing is a thick steel tube. The casing used extensively in construction drilled piles. The casing used to guide the drilling rig to drill the pile hole in the correct location. Also, it can be used to stabilize and prevent the soil from collapse until the concreting of the pile is completed. Furthermore, the casing will be used to hang the steel cage until the concrete is poured. The used casing should be thick and strong enough to resist the imposed stresses during the installation and removal process for temporarily casing. The casing should be clean, smooth, free from encrusted concrete, or any damage that can affect the size and shape of the pile. Figure 1 The casing length will vary according to the purpose of use and the type of the soil. If supporting fluids are used to stabilize the soil, the casing will be used as a guide for the drilling rig. Therefore, the casing length will be short. If the casing is used to support the soil, the casing length should be s...
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

HA type loading

By -
Image
HA type loading was introduced in 1945 in UK. HA is composed of uniform loading and knife edge loading covers all the permitted normal vehicles in Great Britain and it does not cover abnormal vehicles. normal vehicles referred to AW(authorized weight). This covers the vehicle of the maximum gross weight of 44 tons. these vehicles are represented by a uniformly distributed load and knife edge load as shown in figure no:1. Figure 1 construction management: concrete construction course   bridge construction:How to become a bridge engineer course HA type load has been enhanced to cover: impact loads: due to the impact of vehicle wheels with potholes or uneven road surface overloading multiple vehicles occupying the width of the road lane The magnitude of uniformly distributed loads depends on the loaded length. determined from the influence line. for a simply supported beam, the length is equal to span length. UDL W=316*(1/L)^0.67 KN/M for L...
Read more

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

Crosshole Sonic logging test

By -
Image
Cross-Hole Sonic Logging (CSL) Test The Cross-Hole Sonic Logging (CSL) test is a more advanced method compared to conventional integrity testing. It is primarily used to assess the quality of concrete in deep foundations, particularly in cast-in-place piles. Principle of CSL Testing Prior to pile casting, access tubes are securely fixed inside the steel reinforcement cages. The CSL test evaluates potential defects in the pile concrete shaft by measuring: First Arrival Time (FAT): The time taken for the ultrasonic pulse to travel between the transmitter and receiver. Wave Energy: The strength of the received ultrasonic wave. The wave velocity is calculated using the formula: This calculated velocity is then compared to the expected velocity of sound waves in concrete. Lower wave speeds and weak energy signals indicate potential defects, such as voids, honeycombing, or inclusions within the concrete pile. construction management: concrete constructi...
Read more

Bundled Bars

By -
Image
sometimes the required reinforcement bar will not fit for a given section of beam or girder, in this case, we resort to bundling a group of parallel bars, up to four bars can be bundled together,  ACI 7.6.6.2 stating that bundled bars should be enclosed within stirrups or ties, bundled bars should be tied, wired and fastened together to ensure remaining in position whether vertical or horizontal, ACI 7.6.6.3 stating that bars have diameter greater than 36 mm(#11) shall not be bundled in beams, the limitation of bundled bars size is for beam or girders in building, the small size of building members make it unpractical to bundle bars with size larger than 36mm(#11), in bridges the size of members are bigger and therefore it is allowed to bundle up to two bars with size greater than 36mm (#11). figure 1 showing bundle bar arrangements. figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer when two or more ...
Read more

The reasons behind the trimming of pile head

By -
Image
  In general, the bored piles are casted to a level higher than the required pile cut-off level. Pile cut-off level is usually similar or a little bit higher than the blinding level of a pile cap. the process of constructing a cast-in-situ pile involves the following steps: installation of the temporary casing to prevent the soil collapse during the drilling process and to guide the drilling rig. Drilling the pile to the required level and diameter. Installation of a reinforcement cage. Reinforcement cage vertical bars will be extended above the pile cut-off level to improve the bonding with the pile cap. The casting of concrete usually done with a tremie pipe. Tremie pipe will be lowered to the bottom of the pile, and then the concrete will be poured. Once the casting is completed, the temporary casing will be removed. It is a common practice to cast the concrete above the cut-off level. the concrete casted then removed for the following reasons: during the casting process, the se...
Read more