This paper presents the feasibility and relevance of cementitious resins as a bonding agent for near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) strips. Contrary to conventional organic matrices, such inorganic resins offer promising performance when subjected to aggressive environments, especially under thermal distress. Three emerging resins are employed (polyester-silica, ultra-high-performance concrete (UHPC), and geopolymer) to strengthen reinforced concrete beams alongside NSM CFRP. After stochastically simulating various levels of pitting corrosion for a period of 100 years, the outcomes are represented in the beams by reducing the cross-sectional area of steel reinforcement before applying the rehabilitation system. The emphasis of experimental investigations lies in the workability of those resins and the flexural response of the retrofitted beams. Material-level testing reveals that the rheological properties of the resins are not related to their compressive strength. As far as load-carrying capacity is concerned, the beams bonded with polyester-silica outperform the beams with other resins; however, UHPC enables stable degradation over the years. The interfacial characteristics of the resins dominate the mechanical interaction between the damaged internal reinforcing steel and CFRP, thereby altering the tendency of capacity drops, post-yield plateaus, and crack distributions. Through analytical modeling, the provisions of existing design guidelines are evaluated and a modification factor is suggested to promote the cementitious resins for NSM CFRP.

This paper presents an experimental study on the anchorage behavior of column reinforcement subjected to tension in drilled shaft footings loaded under combined axial force and uniaxial bending moment. Large-scale tests were conducted on four footing specimens that were constructed with different column bar anchorage details: straight bars, hooked bars with two different hook orientations, and headed bars. All tension-loaded column reinforcement was shown to yield, regardless of anchorage type. Further, all anchorage types developed stresses in the vicinity of the anchorage region, except for bars with end hooks that were oriented outwards from the base of the column. Properly-oriented hooked bars, considering the internal force flow of the strut-and-tie model, and headed bars developed more uniform stress distributions over their lengths as compared to straight bars. Based on developed stress distributions for the column reinforcement estimated from strain measurements, a critical section was also proposed to establish the anchorage requirement for the column reinforcement in a 3D strut-and-tie model.

This paper documented an experimental study on load transfer mechanisms of six precast concrete (PC) frames with different emulative connections to resist progressive collapse. Load transfer mechanisms, such as compressive arch action (CAA) and catenary action (CA), were observed during loading history, while the CA dominated the ultimate load capacity. The robustness of PC frames assembled by mechanical couplers or U-shaped bars was evaluated experimentally and analytically. To improve the robustness of PC frames assembled by U-shaped bars, two refined strategies were introduced: a) adding additional straight bars in the trough connection, b) replacing U-shaped deformed bars with plain bars. It was found that, with the additional straight bars in the beam troughs, the CAA capacity, CA capacity, and deformation capacity can be increased. Replacing U-shaped deformed bars with plain bars can improve the CA capacity and deformation capacity effectively while it may decrease the CAA capacity slightly. To further understand the load transfer mechanisms of PC frames with different connections, an analytical elaboration was conducted. It was demonstrated that, at the CAA stage, shear force (related to flexural action) dominated the load transfer mechanisms. At the CA stage, shear force still dominated the load transfer mechanisms of the beam-side column interface while tensile axial force dominated the load transfer mechanisms of the beam-middle column interface.

Post-tensioned concrete flat slabs with a high span-to-depth ratio are susceptible to vibration problems. Although the issue was addressed in previous research, there is no final agreement on the effect of prestress level on the fundamental frequency of post-tensioned concrete slabs. Through numerical modeling using ABAQUS-SIMULA software, this paper presents the effect of prestressing forces on the fundamental frequencies of slabs. This paper also examines the applicability and accuracy of the available mathematical models to estimate the fundamental frequency of concrete slabs. Finally, the paper presents two newly proposed mathematical models created by a neural designer program. The first model is to estimate the fundamental frequencies of uncracked concrete slabs, and it is more accurate than the currently available equations. The second proposed model is to estimate the peak acceleration of uncracked concrete slabs, and it is applicable for dynamic motion of forcing frequency 2 Hz and damping ratio 2%.

Shear failures are one of the most brittle modes of response in reinforced concrete columns subjected to earthquake-induced lateral drifts, notably if the failure occurs before the flexural strength is reached. Columns exhibiting this failure mode are termed shear-critical and are associated with the loss of the column's axial load-carrying capacity. Using a database of tests on thirty-eight large-size rectangular and square columns that exhibited this mode of failure, this paper reviews nine methods published in the literature and compares their predictive capabilities. This paper shows significant differences between the methods, with the method in ACSE 41-13 being assessed as the most accurate.