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Pre-stressed high-strength concrete pipe piles (PHC pipe piles) have been widely used in actual soft foundation treatment projects due to their reliable quality, fast construction, assembly line production, and environmental friendliness. However, large-scale slip damage still occurs in construction projects. In order to reduce and avoid such accidents, a highway in Guangdong (section K31+100~K31+388) was taken as an example for this study. Plaxis 2D software (V22.01.00) was used to establish a PHC pipe pile composite roadbed model and investigate the effects of tie beam form, pile lengths, pile spacings, pile verticality, and embankment filling loading modes on the settlement and stability of the composite roadbed. The results show that the original treatment plan, which had the form of a PHC pipe pile with caps, had a low horizontal bearing capacity and a poor anti-disturbance ability, leading to the occurrence of a landslide accident. A comparison of different structural forms revealed that the longitudinal and transverse tie beam form was the most stable, followed by the transverse tie beam form, longitudinal tie beam form, PHC pipe pile form with caps, and PHC pipe pile form without caps. Compared to the structural form of PHC pipe piles with pile caps, the stabilities of the transverse tie beam form and the longitudinal tie beam form were improved by 42.47% and 38.61%, respectively, while that of the longitudinal and transverse tie beam form was improved by 50.87%. The application of longitudinal and transverse tie beams effectively reduced the settlement of the composite roadbed, as confirmed by both measured data and finite element analysis. This structure achieved the desired vertical settlement control and lateral anti-slip effects.

The purpose of this study is to investigate the behavior of V-shaped reinforced concrete columns under three different angles of inclination (30°, 40°, and 50°), and to clarify the effect of is angle on the load carrying capacity and failure mode of columns. Six experimental specimens were prepared, three of which were equipped with the upper tie beam, while the other three were without the tie beam. The results showed that the bearing capacity of the columns decreased with increasing angle of inclination, as it decreased by 7.5% and 9.3% at angles of 40° and 50°, respectively, compared to angle 30° in the presence of the tie beam. While, the capacity decreased by 6.7% and 8.4% at 40° and 50°, respectively, in the absence of the tie beam compared to angle 30°. The effect of the beams had a clear impact on increasing the ultimate load values and the failure pattern for angles exceeding 40°, as it was noted that the load values for those columns with inclination angles (30°-40°) had the opposite effect, as the failure was concentrated in the joint and tie beam area. These results reflect the importance effect of the angle of inclination and the presence of the tie beam in improving the structural performance of concrete columns, which contributes to the design of more stable and efficient structures under different loads.

Due to short duration and high energy characteristics, near-fault earthquakes showed more destructive damage on bridges. For double-column hige-pier rigid frame bridges, tie-beams between double-columns play an important role in seismic resistance. Therefore, the influence of traditional reinforced concrete tie-beams and energy dissipation braces on the seismic performance of high-pier rigid frame bridges under near-fault earthquakes were analyzed base on the seismic vulnerability analysis. It was showed that as the number of tie beams increases, the plastic hinge curvature on the top and bottom of the pier gradually decreases, and the probability of exceeding each damage state also gradually decrease. Additionally the energy dissipation braces can greatly reduce the seismic response and the damage probability of the bridge structure.

This study investigates the probabilistic seismic damage characteristics of a five-span RC simply supported girder bridge with double-column piers designed for a high-speed railway (HSR). The objective is to assess the bridge’s fragility by developing a refined nonlinear numerical model using the OpenSEES (Version 3.3.0) platform. Incremental dynamic analysis (IDA) was conducted with peak ground accelerations (PGA) ranging from 0.05 g to 0.5 g, and fragility curves for pier columns, tie beams, and bearings were developed. Additionally, a series–parallel relationship and a hierarchically iterated pair copula model were established to evaluate system fragility. The results indicate that as PGA increases, the damage probability of all bridge components rises, with bearings being the most vulnerable, followed by pier columns, and tie beams exhibiting the least damage. The models accurately simulate the correlations between members and system fragility, offering valuable insights into the bridge’s performance under seismic conditions.

Due to the complexity of the actual geotechnical environment, the backfill compaction design theory and calculation method are not reflected in the current specification. Therefore, in order to investigate the effect of the hydraulic compactor on the foundation structure during the treatment of the backfill of an independent foundation under a column, the Menard formula was modified. At the same time, relying on an independent foundation project under a column in Jinan, the dynamic model of compactor tamping backfilling soil was established. The applicability of the calculation formula is verified by simulating the single-point multiple tamping on the backfill directly above the foundation tie beam, and the influence law of two factors, the thickness of the backfill and the tamping energy, on the force of the foundation tie beam is elucidated. The results show that after reaching the optimum number of tamping, the cumulative soil settlement and the effective reinforcement depth of tamping show a stable trend, and their simulation results are in good agreement with the analytical solution, which provides a supplement to the relevant safety standards. At this critical point, the force on the tie beams peaked and showed up and down fluctuations under the subsequent ramming action. The tamping action of the compactor has a significant effect on the structural forces within the effective reinforcement range, and there is a negative correlation between the magnitude of the structural forces and the thickness of the backfill. According to the numerical calculation results to choose the best construction programme, the on-site monitoring shows that under 42 KJ tamping energy and 1.5 m single backfilling thickness, the tie beam reinforcement stress reaches 18.5~55.5% of the specification warning value, which meets the safety standard. The research results of this paper can provide important guidance for the hydraulic tamping treatment of an independent foundation backfill project.

The steel-concrete interface (SCI) is extensively acknowledged to affect the durability of reinforced concrete. The main objective of this paper is to conduct a state-of-the-art review that contributes to sufficient knowledge on the determination of the SCI properties and its effect on the overall performance of reinforced concrete elements. The physical characteristics at the SCI are influenced by segregation, flow, hydration, and drying shrinkage of concrete, hence affecting the presence of voids and cracks within this interface. The bond strength is one of the measures of the SCI and this is conducted through pull-out, push-in, and tie-beam testing. It was shown that the rebar shape and diameter, the anchorage length, the concrete grade strength, binder type (geopolymer concrete), and the distribution of aggregates have a significant effect on the interface properties and behavior, where geopolymer concrete offered improved bond behavior over conventional concrete. Various studies have demonstrated that the presence of the steel-concrete interface and the application of mechanical stresses contribute to the flow transfer (inflow/outflow) through the reinforced concrete structure. Some of these studies focused on the initial state of the SCI within the structure, and some conducted tests with shear loading on the SCI. Regarding the transfer properties at the SCI, it was shown that the presence of steel rebar, crack dimensions, degree of saturation of concrete, and the concrete mix design, influence the permeability of the concrete, specifically at the vicinity of the SCI, because of the development of micro-cracks at the interface. In other studies, the shear stresses were also found to affect the transfer properties through the SCI. Researchers have implemented several software solutions such as finite element models on ABAQUS and mesoscale numerical simulations and have used machine learning models that predict and verify the effects of bond failure behavior at the SCI. Good agreement was established between the numerical and actual experimental results. The influence of different exposure conditions on the steel-concrete interface that change throughout time needs to be dealt with, which includes moisture-related environmental conditions, variation in temperature, and chemical exposure. Furthermore, the influence of structural loading, such as “creep effect”, deterioration (ageing) of material must be studied at the interface. The studies were limited to short-term behavior.

In many areas of developing countries, the access to fresh water is limited even today. Aqueducts are the major structures in water supply and diversion schemes when carrying the water over natural and artificial obstacles such as valleys, rivers, roads, railway lines, canals etc. During an earthquake, the effect of water sloshing on the walls of aqueduct and the resulting hydrodynamic forces is often neglected. In this study, the analysis is carried out for a single span elevated aqueduct using finite element analysis, in which the structure is discretized into smaller elements. The structure is modelled using solid elements in Staad Pro V8i software for different loads. The behavioral response of aqueduct structure subjected to hydrostatic loads and dynamic loads due to seismic ground excitation has been analyzed. It has been observed that the structure is more vulnerable to dynamic loads compared to hydrostatic loads. The effect of dynamic loads due to sloshing of water under seismic forces is predominant. The stresses induced by hydrodynamic loads are observed to be 2.4 times more than hydrostatic loads.

Research on the configuration and mechanical performance of arch-column-tie beam joints, which combine features of arch-tie beam joints and tubular joints, remains limited, particularly for long-span structures subjected to heavy loads at high building stories. This study focuses on a joint in an engineering structure comprising a circular arch beam, a square-section inclined column, and a tie beam, where both the arch and the inclined column are concrete-filled steel tube (CFST) members. A novel joint configuration was proposed, then a refined finite element model was established. The joint’s mechanical mechanism and failure mode under axial compression in the arch beam were investigated, considering two conditions: the presence of prestressed high-strength rods and the failure of the rods. Subsequently, a parametric study was conducted to investigate the influence of variations in the web thickness of the tie beam, the steel tube wall thickness of the arched beam, the steel tube wall thickness of the supporting inclined column, and the strength grades of steel and concrete on the bearing capacity behavior and failure modes. Numerical simulation results indicate that the joint remains elastic under the design load for both conditions, meeting the design requirements. The joint reaches its ultimate capacity when extensive yielding occurs in the tie beam along the junction region with the circular arch beam, as well as in the steel tube of the arch beam. At this stage, the steel plates and concrete within the joint zone remain elastic, ensuring reliable load transfer. The maximum computed load of the model with prestressed rods was 2.28 times the design load. The absence of prestressed rods could lead to a significant increase in the high-stress area within the web of the tie beam, decreasing the joint’s stiffness by 12.4% at yielding, but have a limited effect on its maximum bearing capacity. Gradually increasing the wall thickness of the arch beam’s steel tube shifts the failure mode from arch-beam-dominated yielding to tie-beam-dominated yielding along the junction region. Increasing the steel strength grade is more efficient in enhancing the bearing capacity than increasing the concrete strength grade. Finally, a design methodology for the joint zone was established based on three aspects: local stress transfer at the bottom of the arch beam, force equilibrium between the arch beam and the tie beam, and the biaxial compression state of the concrete in the joint zone. Furthermore, the construction process and mechanical analysis methods for various construction stages were proposed.

This paper describes results of numerical analyses of reinforced lintels made of autoclaved aerated concrete built into unconfined walls and walls confined with reinforced concrete. The combination of the Menétrey–Willam elastic-plastic failure criterion (M-W-3) and the Rankine criterion was used for numerical analysis of masonry. The parameters were determined by laboratory tests. Rebars were modelled using the Huber–Mises–Hencky yield criterion. The numerical model included interface elements att the interface between masonry units, at interfaces between reinforced concrete and masonry, and at interfaces between elements of test stands with a model using the Coulomb–Mohr (C-M) criterion. The majority of parameters of interface elements were assumed from laboratory tests. Results of numerical analysis were compared with laboratory tests. Results of numerical analysis and experiments were compatible in the range of load-carrying capacity of models and the failure method.

Several reinforcing schemes are illustrated that are based on the loading characteristics of typical country masonry school buildings with sparsely spaced transversal walls and large depth. From the seismic damage observed following the Wenchuan Earthquake, the effects of reinforcing schemes, tie-columns and tie-beams on the seismic resistance of masonry buildings are analyzed. The concept of improving the ductility of these types of buildings is presented. Finally, some suggestions are proposed for the design of masonry buildings with sparsely spaced transversal walls and large depth.