Video from my YouTube channel

Subscribe to My You tube channel

Bridge continuous multi-span deck compared to simply supported multi-span deck

By -
simply supported multi-span deck required an expansion joint above each support(pier) to maintain the separation between deck spans so it will work as a simply supported deck. the number of the expansion joint and bridge bearings in simply supported multi-span deck is significantly greater compared to continuous multi-span deck.




Adopting continuous deck over simply supported deck for bridge construction will contribute to the reduction of construction and maintenance cost by reducing numbers of expansion joints and bearings. besides reduction in cost, it will reduce the inconvenience of road commuter resulted from road closure for maintenance.
 
Choosing continuous deck over a simply supported deck. will contribute to reducing deck depth through deck sucker principle. reduction of depth will reduce the dead-load of superstructure and this will be followed by a reduction of pier and foundation size. This will play an important part in reducing the cost of construction and producing economical design. However, some designer preferred to add more expansion joints to guard against the possible occurrence of differential settlements.





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

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

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

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

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

Elastomeric expansion joint

By -
Image
Elastomeric expansion joints can accommodate a wide range of movement 30-800 mm, and it can easily installed and provide a smooth ride with minimal noise and vibration. It can be found in different formats. Each format accommodates different type of movement. Figure 1 Elastomeric joints consist of reinforced neoprene. Steel plates shall be embedded in the neoprene molded section to meet the structural requirement. Figure no:2 shows elastomeric expansion joint different components. construction management: concrete construction bridge construction:How to become a bridge engineer Figure 2 The elastomeric joint shall be skid resistance, armored and it should provide  smooth riding, and it shall be durable.  Installation of joint shall be strict accordance to specification and manufacturer recommendation.  construction management: concrete construction bridge construction:How to become a bridge engineer Ins...
Read more

Repairing of concrete bulging

By -
Image
Improper designing and installation of formwork for a concrete member can result in concrete Bulging. During the placing and compacting of concrete, forms may deflect largely in the weak areas. The deflection of forms will cause concrete to expand at this location, and this known as concrete Bulging. Concrete Bulging will spoil the appearance of a concrete member. Therefore we should always ensure that the forms are appropriately installed, and it is sufficiently supported to resist the concrete during placing and compacting. Bulging should be repaired in case we couldn't avoid it. The solution of concrete Bulging, offset, or surface irregularities are surface grinding. However, excessive surface grinding can weaken the concrete.  Figure 1 If the bulging or surface irregularities are small, grinding of concrete surface will be sufficient to remove surface irregularities. If the Bulging of concrete is significant, then the concrete should be chipped, and the surface...
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

Balanced section, tension controlled section and compression controlled section of reinforced concrete beams

By -
Image
RC beams where reinforcing steel yields at the same time in which concrete strain at extreme compression fiber is 0.003(concrete reach it is flexural capacity at this value of strain) called balanced section. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer in compression controlled section the strain at extreme fiber for concrete reached 0.003 before steel yield. in this case, the section is over reinforced. for compression controlled section slight and unnoticeable deflections will occur to RC beams. this will result in a sudden failure without any warning in case of overloading. these members called as brittle members and it should be avoided.                               Figure 2 in tension controlled members. reinforcing steel yields before the concrete strain at extreme compression fiber reaches 0.003. in this ty...
Read more