This study presents the shear behavior of reinforced concrete (RC) T-beams with innovative steel stirrups hybridized in the longitudinal direction with a fiber-reinforced polymer (FRP) composite. Six beams were experimentally tested: three beams were reinforced with the hybrid steel-FRP stirrups, and the others served as control samples and were reinforced with conventional steel stirrups. Furthermore, a two-dimensional finite-element (FE) model was created and executed using FE analysis software to examine the effect of several influential parameters, including the type and amount of FRP used in producing the hybrid stirrups. Large-scale beams reinforced with carbon FRP (CFRP) stirrups were numerically simulated before and after replacing the transverse CFRP reinforcement with steel-FRP stirrups. Compared with conventional RC beams, concrete beams reinforced with steel-FRP stirrups successfully showed a considerable increase in the beam shear strength and deformability. Moreover, hybrid steel-FRP stirrups can provide design engineers with a new, flexible design to control both the structural response and the construction cost.

In this study, a stress-strain model of fiber-reinforced polymers (FRPs)-confined concrete based on the lateral confinement stiffness was adopted to simulate the lateral response of RC columns retrofitted with external FRP jackets and tested under axial and lateral loads. The adopted model and other five-stress-strain models (established in former studies) were comparatively studied to simulate the seismic response of eight RC-circular columns retrofitted with FRP jackets and experimentally tested under both axial and lateral loads. Compared to the experimental results, the simulation results indicated that all stress-strain models could not identify properly the ultimate lateral displacements of the simulated columns. The adopted stress-strain model was revised to consider the effect of a key influential parameter (eccentricity ratio), which showed a critical impact on the simulation of the seismic response of RC-columns under combined bending and axial loadings. Finally, the proposed model was evaluated in predicting the lateral response of additional three columns and the simulation results exhibited a good agreement with the experimental results.

Cooling of buildings is an essential target for engineers and builders in the hot arid climate of Egypt. Performance of inclined solar chimney with passive cooling tower (SCPC) was studied. The system was integrated into a single room built in Assiut University (El-Gorib site) in Assiut, Egypt. Testing of indoor environment for the room with passive cooling was done during August and September 2015. A passive cooling technique was integrated inside a short wind tower made from expanded paper (wet pad) 0.1 m thick. A water tube was installed on the top of the expanded paper with small nozzles. Water is recirculated through the system using water pump. A reduction of room indoor temperature was observed with the integrated system (SCPC). There is a significant reduction of indoor temperature between 6 and 7 K due to passive cooling with surface temperature 19.4 °C for the cooling pad. The relative humidity did not exceed 57% most of the time. The maximum air speed inside the solar chimney was 3.5 m/s under the effect of a high solar radiation of 890 W/m2. The findings show that SCPC system achieves comfortable thermal conditions with a significant improvement in building energy conservation. The result of development this new cooling system helps to develop building code for low energy houses in Egypt and propose a new system to be integrated in the housing project of people with low income.

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The design of segmental lining of TBM tunnels requires a special experience and knowledge. One of the influencing factors affecting the stresses induced in the lining, which is often ignored in the design of tunnels, is the effect of joint which connects each two segments, and known as the longitudinal joint, or the tunnel hinge. In this paper curves for the joint rotational stiffness under the effect of normal force and moment are presented based on a numerical modelling of tunnel hinge, considering the steel reinforcement of the segment, plasticity of concrete, decoupling and properties of segmental joints. The result obtained from the curves is directly coupled with the finite element program FINAL (Swoboda 2007), and hence it can be applied in the design of segmental lining. The numerical modelling of the tunnel hinge consists of two concrete parts represent the segments, the length of each concrete part equals its thickness, and the width of the hinge equals half of the thickness of the segment, the numerical model is based on LST elements for concrete considering a new explicit formulation of concrete plasticity, and the decoupling is simulated with an interface element. A program ‘Hinge’ was made depending on the results of the numerical modelling of tunnel hinge, this program can calculate the value of the rotation of the hinge as a function of the normal force and bending moment, also the program can expect the type of the deformation in the hinge however it is elastic or plastic, at the end of this paper there is an application on TBM tunnel by using the results of program Hinge.

The design of segmental lining of TBM tunnels requires a special experience and knowledge. One of the influencing factors affecting the stresses induced in the lining, which is often ignored in the design of tunnels, is the effect of joint which connects each two segments, and known as the longitudinal joint, or the tunnel hinge. In this paper curves for the joint rotational stiffness under the effect of normal force and moment are presented based on a numerical modelling of tunnel hinge, considering the steel reinforcement of the segment, plasticity of concrete, decoupling and properties of segmental joints. The result obtained from the curves is directly coupled with the finite element program FINAL (Swoboda 2007), and hence it can be applied in the design of segmental lining. The numerical modelling of the tunnel hinge consists of two concrete parts represent the segments, the length of each concrete part equals its thickness, and the width of the hinge equals half of the thickness of the segment, the numerical model is based on LST elements for concrete considering a new explicit formulation of concrete plasticity, and the decoupling is simulated with an interface element. A program ‘Hinge’ was made depending on the results of the numerical modelling of tunnel hinge, this program can calculate the value of the rotation of the hinge as a function of the normal force and bending moment, also the program can expect the type of the deformation in the hinge however it is elastic or plastic, at the end of this paper there is an application on TBM tunnel by using the results of program Hinge.

The design of segmental lining of TBM tunnels requires a special experience and knowledge. One of the influencing factors affecting the stresses induced in the lining, which is often ignored in the design of tunnels, is the effect of joint which connects each two segments, and known as the longitudinal joint, or the tunnel hinge. In this paper curves for the joint rotational stiffness under the effect of normal force and moment are presented based on a numerical modelling of tunnel hinge, considering the steel reinforcement of the segment, plasticity of concrete, decoupling and properties of segmental joints. The result obtained from the curves is directly coupled with the finite element program FINAL (Swoboda 2007), and hence it can be applied in the design of segmental lining. The numerical modelling of the tunnel hinge consists of two concrete parts represent the segments, the length of each concrete part equals its thickness, and the width of the hinge equals half of the thickness of the segment, the numerical model is based on LST elements for concrete considering a new explicit formulation of concrete plasticity, and the decoupling is simulated with an interface element. A program ‘Hinge’ was made depending on the results of the numerical modelling of tunnel hinge, this program can calculate the value of the rotation of the hinge as a function of the normal force and bending moment, also the program can expect the type of the deformation in the hinge however it is elastic or plastic, at the end of this paper there is an application on TBM tunnel by using the results of program Hinge.