In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses its careful mitigation through experimental identification and numerical analysis to enhance the safety and sustainability of buildings by reducing the probability of failure risk for these RC beams. Nine of the ten RC beams that were tested had strengthened, and one had not. Internal prestressing (IP) within the beam body, external prestressing NSM (PNSM), internal embedment (IE) inside the beam with or without prestressing, and NSM are the strengthening technologies that were employed. The range of the extra shear reinforcement ratios (μs) was 0.87% to 1.60%. We investigated how strengthened beams behaved structurally in terms of the cracking load, ultimate load, load–deflection response, ultimate deflection, and stiffness. The insertion of five pairs of PNSM rods (μs = 1.45%) and five pairs of IP rods (μs = 1.6%), respectively, increased the beams’ shear capacity by 57.8% and 70.4%. Shear capacity increased by 23.2% when three pairs of IE rods (μs = 1.02%) were installed. The prestressing location had an impact on shear capacity, with the interior case surpassing the external one. Compared to the control, the stiffness of the strengthened beams rose by 20%, 82%, and 84.4% when three, four, or five pairs of internal prestressing rods were added. A formula is proposed to calculate the shear capacity of all beams strengthened using various methods.

Slab-on-ground (SOG) serves as a fundamental structural element in contemporary buildings and infrastructure. In recent years, the adoption of fiber-reinforced concrete (FRC) for SOG has gained significant traction due to its enhanced mechanical performance and durability. The design methodologies for (SOG) primarily rely on the flexural slab capacity (FSC) to determine the required slab thickness. This process involves calculating the modulus of rupture (MOR) of the concrete beam, following the guidelines established by AASHTO T 97 or ASTM C78 standards. All prior experimental findings have demonstrated that the MOR is significantly lower than the FSC, indicating that it cannot be relied upon to accurately predict the FSC. Consequently, employing the MOR to predict FSC would result in an underestimation of the FSC, necessitating excessive thickness. Therefore, this study aims to develop a more accurate predictive equation for FSC by using MOR and key influencing parameters of SOG, ensuring a more efficient and optimized slab thickness design. The predictive equation is derived using statistical procedures based on an extensive dataset of over 100 SOG cases from previous literature. The findings indicate that the FSC is highly influenced by the MOR, subgrade reaction modulus (k), fiber volume content (V _f ), concrete compressive strength (f _c '), and SOG width (W _SOG ). In addition, the proposed equation is evaluated in comparison with the most widely utilized (MOR) equations. The study demonstrates that the proposed equation yields the highest accuracy in predictions, exhibiting a coefficient of variation of 40%, in contrast to 88% for the Eurocode equation and 84% for the ACI equation.

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Temperature variations have a significant impact on the performance and durability of rigid (concrete) pavement. As concrete is subjected to daily and seasonal temperature changes, it experiences thermal expansion and contraction. These movements, if not properly managed, can lead to cracking, joint deterioration, and loss of structural integrity. The pavement system is adversely affected by intense heat and significant flooding. This study aims to analyze the impact of several parameters on the performance of rigid pavement under typical, thermal, and flooding situations. This study investigates the properties of concrete and the dimensional design of rigid pavement with FEACONS IV software to assess their impact on the performance of concrete pavement during thermal and flooding conditions. The main conclusions of this study derived from the FEACONS IV analysis are as follows. Rigid pavement can enhance load-carrying capacity due to a lower elastic modulus, adequate flexural strength, and aggregates with a lower coefficient of thermal expansion. Increased thickness of concrete slabs and shorter slab lengths assist in minimizing load- and temperature-induced stresses. The increase in the subgrade modulus reaction value during flooding conditions improves pavement strength. However, in higher thermal conditions, a higher subgrade reaction modulus can increase the stress induced by temperature and load. Rigid pavement using porous limestone aggregate exhibits a reduced elastic modulus and coefficient of thermal expansion, suggesting higher resilience compared to rigid pavement composed of river gravel or granite. The findings suggest that higher thermal conditions will cause pavement damage. Agencies need to account for higher temperatures while designing and maintaining pavement. Flooding saturates the concrete pavement and subgrade layer, adversely affecting its performance over time.

Reinforced concrete (RC) flat slabs are widely used in modern structures due to their architectural flexibility, but they often require strengthening to enhance their flexural performance and service life. This study investigates the structural behavior of RC flat slabs externally strengthened using near-surface-mounted textile-reinforced mortar (NSM-TRM) systems incorporating glass fiber-reinforced polymer (GFRP) meshes. The experimental program included seven slab specimens: one unstrengthened control and six strengthened slabs with varying GFRP layer numbers, reinforcement orientations (orthogonal or diagonal), and installation methods (epoxy bonding or mechanical anchorage). The results revealed that both orientations substantially enhanced flexural performance relative to the unstrengthened slab, with the orthogonally strengthened specimen achieving the highest ultimate load increase (24%) among all tested configurations. This behavioral advantage is attributed to the alignment of orthogonal GFRP strips perpendicular to the dominant tensile crack directions emanating from the slab center, which maximizes crack-bridging efficiency and stress transfer capacity. A three-dimensional finite element model (FEM) developed in ABAQUS was validated against experimental results with coefficients of variation not exceeding 5.86%. The findings confirm that reinforcement orientation, number of GFRP layers, and anchorage method are the key factors governing the flexural performance of GFRP-based NSM-TRM systems for flat slab strengthening, as collectively quantified through ultimate load capacity, post-cracking stiffness, and energy absorption.