A study of Al-Rayhanna Bridge (Iraq, Anbar Province) concerned with examining elastomeric bearing pad dynamic behaviour against changes in traffic speed and girder deflection. The areas of maximum deflection were being located at midspans of the girders, especially under truck or underneath truck lanes. One of the key contributions of the work was the application of the deflection measurements of the Linear Variable Differential Transformer (LVDT) for the estimation of car speeds, and a very welcoming mean value of 40.95 km/h (the visual timing correlations being >95 per cent), showed that structural measurement can be employed in reliable traffic analysis. The new bridge was defined by reduced damping ratio (3-4 % compared to 5-6 % of the old bridge) accounting for varying abilities to absorb and release energy. Thus, the new bridge appeared to require less balance restoration energy (1.5-2 seconds / 0.5-0.67 Hz) than the old bridge exhibiting faster stabilization (1-1.5 seconds / 0.67-1 Hz). The rate of amplitude decay also varied quite radically: 20-25 per cent per cycle for the new bridge compared to 30-35 per cent for the old bridge. Structural design and climatic dependent factors , indicates the significant role played by adopting dynamic factors - such as damping, energy dissipation and deflection patterns in bridge structure design and maintenance to guarantee long-lasting structural integrity and safety. These observations give conclusive feedback on upcoming resilient bridge construction, also the field of material science and traffic engineering
This study investigates the seismic performance of a nine-storey reinforced concrete building located in Seismic Zone 3, focusing on the effectiveness of viscous dampers in enhancing structural resilience. With increasing seismic risks, the integration of damping systems has become critical for mitigating vibrations and improving building safety. The research evaluates four configurations: a fixed-base building with no dampers, buildings with corner dampers featuring uniform and varying force capacities, and a building with middle dampers. The Equivalent Static Load (ESL) and Response Spectrum study (RSA) methods are used in the ETABS 2021 research to look at important factors such the natural period, storey stiffness, storey drift, storey displacement, and overturning moments. These steps are based on the UBC 97 criteria. The results show that viscous dampers do assist structures stay standing during earthquakes. Buildings with corner dampers that could handle different amounts of stress had a natural period that was 37.5% shorter. This means that they were stiffer and could respond to seismic shocks faster. The storey's stiffness went down by 16.7%, and the periods of overturning went down by 5.7%. This shows that the dampers did a great job of getting rid of energy. Also, the maximum storey displacement and drift were 41.6% and 48.14% lower than in the fixed-base model, respectively. These figures show how important it is to put dampers in the right places, especially at corners where the force capacity changes, to make buildings more resistant to earthquakes. The study's conclusion is that viscous dampers make multi-story structures in moderate seismic zones much safer by making them less likely to break and improving how effectively they perform. This study gives engineers and designers important information that makes them desire to use current dampening technologies in tall buildings to make them safer during earthquakes.
In this study, the structural behaviour of RC-deep beams of glass fibre-reinforced polymer (GFRP) rubberized concrete is investigated. Rubberized concrete is manufactured by replacing fine sand aggregate with rubber crumbs in volumetric replacement ratios. The main variables were the crumb rubber content (0%, 10%, and 20%) and the main reinforcement ratio. Tested Six samples of deep beams with different dimensions (b = 150, h = 300 mm, L= 1400 mm) were under a four-point load until failure. The parameters under investigation were the mechanical properties of mixtures, load-midspan deflection curves, toughness, and the load-strain relationship. The results indicate that the increased crumb rubber content led to a decrease in the mechanical properties of rubberized concrete mixtures. It was found that the behaviour of all samples of rubberized concrete affected the deflection load curve, the ultimate load, and the increase in deflection. The sample R2-10% Rub showed the highest toughness among the tested samples, with an increase of 301.6% compared to the reference.
The present study, the effect of changes that developed in concrete structures with time is presented. Two way slab investigated experimentally by [1]was analyzed using finite element method by ANSYS commercial program. Many parameters studied such as length to thickness ratio, reinforcement ratio and ultimate load ratio. The slab with dimension (2360*2360*63) mm and reinforced with different types of materials such as steel bars ,GFRP and CFRP (fiber reinforced polymer) bars . The results show that the strain increase gradually with time after apply the load. It can see that the strain in steel model increase with ratio of 19.98% when the load increase from 75% to 90%,and decrease with ratio 50% when the load decrease from 75% to 50% .That is, the change by increasing the strain is less and slower than the change by decreasing the strain, since the strain when dropping the load is less than the strain when lifting the load, because the structure has not undergone and its stiffness is still high and it is trying to recover its original shape. It increases significantly at the beginning, and then the difference decreases or stabilizes approximately after 330 days.
The design of reinforced concrete structures has traditionally relied on empirical techniques based on experience or experimental research on actual structural members. Although this approach produces a high level of precision, it is usually exceedingly costly and time-consuming. This paper studied the convergence between theoretical analysis (ACI 318-19 Equations) and numerical analysis (FEM) of eleven one way reinforced concrete slab specimens casted by shotcrete contains three types of plastic fibers including waste plastic (PET), polypropylene (PP), and hybrid (PET+PP) fibers with three addition ratios (0.35%, 0.7%, and 1%) for each type. The results concluded that the numerical analysis (ANSYS FE model) showed a good agreement with the theoretical (ACI 318-19) of one-way slab in terms of ultimate load, with a variance, and standard deviation equal to 0.00076, and 0.027 respectively. Hence, ANSYS v15 software can be used for the analysis of reinforced concrete slabs casted by shotcrete contain waste plastic fibers and polypropylene fibers.
The buckling analysis of Euler-Bernoulli beam resting on two-parameter elastic foundation (EBBo2PEF) has important applications in the analysis and design of foundation structures, buried gas pipeline systems and other soil-structure interaction systems under compressive loads. This study investigates the buckling analysis of EBBo2PEFs. The governing differential equation of elastic stability (GDiES) is derived in this work using first principles equilibrium method. In general, the GDiES is an inhomogeneous equation with variable parameters for non-prismatic beams under distributed transverse loadings. However, when transverse loads are absent and the beam is prismatic the GDiES becomes a fourth order ordinary differential constant parameter homogeneous equation. General solution to GDiES is obtained in this work using the classical trial exponential function method of solving equations. Two cases of end supports were considered: simply supported ends and clamped ends. Boundary conditions (BCs) were used to obtain the characteristic buckling equations whose eigenvalues were used to determine the critical buckling loads for two cases of BCs considered. It was found that the method gave exact solutions for each of the BCs. The critical elastic buckling load coefficients for dimensionless beam-foundation parameter and ranging from for simply supported EBBo2PEFs were identical with previous results that used Stodola-Vianello iteration methods and finite element method. Similarly, the critical buckling load coefficients for and are identical with previous results that used Ritz variational method.