Curious Civil Engineer

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...

  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 ...

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...

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. ...

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...

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 ...

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...

The buckling of the unsupported beam with any dimension even narrow and deep is a rare occurrence. If the beam subjected to appreciable lateral torsion. ACI code [10.4.1] stating that lateral support is not required to placed closer than 50 times b, where b is the least width of compression face or flange.however, it must be considered in determining the maximum spacing for lateral support. construction management: concrete construction bridge construction:How to become a bridge engineer Skin Reinforcement for Deep Beams ACI code [10.6.7] stating that skin reinforcement shall be added for beams with depth h is 400 mm or more, the purpose of this reinforcement is to control cracks in the upper part of the tension zone, this reinforcement will be distributed in both vertical faces of the beam within a distance of h/2 from the tension zone as shown in figure 1, Figure 1 construction management: concrete construction bridge construction:How to become a br...

Design a one-way slab for the inside of a building using the span, loads, and other data given in  Figure 1. Normal-weight aggregate concrete is specified with a density of 145 pcf. (assuming cover 3/4 in) Figure 1 The minimum thickness for one-way slab simply supported=L/20 using table 1(ACI 9.5.2.1) h=10/20=0.5=6in Table 1 construction management: concrete construction bridge construction:How to become a bridge engineer now we will calculate d=(6-3/4(cover)-1/4(estimated as half diameter of reinforcement) d=5 in  now we will calculate dead load concrete density=145pcf, Usually 5 pcf is added to account for the weight of reinforcement, so 150 pcf is used in calculating the weight of a normal-weight concrete member. dd=(6in*ft/12)*1*150/=75 lb/ft LL=200*(1)=200lb/ft Wu=1.2*75+1.6*200=410 lb/ft maximum moment for simply supported span =(Wu*L^2)/8 =(410*10^2)/8=8/=5,125lb-ft=61,500lb-in now we can calculate  ...

experimental tests confirm that the strain varies in proportion to a distance from the neutral axis in compression and tension zone within and near the ultimate stress. compression stress will vary linearly as long the maximum stress is less than 0.5fc'. once the stress exceeds 0.5fc' the distribution of compression stress will change from linear distribution to the shape shown in figure 1. compressive stress will vary from zero at the neutral axis to a maximum value at or near the extreme fiber. neutral axis location and stress variation will differ from a beam to another. this variation depends on several factors such as magnitude and history of post loading, shrinkage, creep and speed of loading. construction management: concrete construction bridge construction:How to become a bridge engineer Figure 1 for simplification whiteny replaced the curved stress block with a rectangular stress block as shown in the figure 2. compressive stress assumed to ...