Papers by Keyword: Opening

Abstract: The presence of web openings in the shear span significantly impacts the structural behavior of reinforced concrete (RC) beams, affecting both shear capacity and crack propagation. This study explores the feasibility of strengthening web openings in the shear zone of RC beams using iron-based shape memory alloy (Fe-SMA) bars through numerical analysis with ABAQUS software. The investigation considered various web opening shapes; diamond, circular, and square strengthened with pre-stressed Fe-SMA bars. Results showed that web openings notably decrease the ultimate loads of beams by 53%, 44%, and 39% for square, circular, and diamond shapes, respectively. However, pre-stressed Fe-SMA bars enhanced the shear capacity of beams with unstrengthened web openings by approximately 60%, making their behavior comparable to solid beams. The proposed strengthening technique was most effective for diamond web openings, nearly restoring both shear strength and stiffness, while circular openings recovered nearly 90% of shear capacity and square openings about 75%. Additionally, Fe-SMA bars effectively controlled cracking at the corners of the openings. This study highlights the importance of strengthening web openings in RC beams, especially in shear zones, and provides significant insights into enhancing such beams, contributing to safer structural designs. Further laboratory experiments are recommended to validate and extend these numerical findings.

Abstract: To validate the accuracy of ANSYS V.19, an experimental model based on a previous study was used to determine the typical values of crack pattern, ultimate load, and deflection. The model was a flat slab with an internal column with dimensions of 1000 × 1000 × 100 mm³. Four groups used a slab with an edge column in parametric research. The first group studied the opening size relative to the column face. The second group of specimens studied opening sizes close to column corners. The third group consisted of four specimens: two had openings in front of the column face and two in front of the column corner to study how opening distance affected flat slab behaviour. The fourth group examined the optimum opening arrangement in slabs with two openings around the column. The findings showed that flat slab openings at the column corner had higher ultimate load capacity than those at the column face; however, increasing opening dimensions beyond the column dimension decreases punching shear capacity. If the column needs two openings, place them on opposite faces or near the corners; this minimizes ultimate load reduction.

Abstract: The subject of the article is a comparison of behavior of a precast reinforced concrete infill shear walls with an opening with different types of reinforcement. These are the walls that can ensure stiffness of the frame structure against horizontal load. Studied walls with an opening represent cases of how the wall can be reinforced prior to the implementation of an additional opening. The influence of the so called “sleeping reinforcement” is studied. This is a reinforcement that would take effect only after the additional opening has been made. The wall elements are first subjected to experimental verification. Subsequently, the results from the experiments are verified by non-linear models, which represent the individual elements during the experiment. Based on these models, a parametric study is performed, where the influence of an opening size in these infill shear walls is studied on their load - bearing capacity and stiffness.

Abstract: The subject of the article is a comparison of the precast reinforced concrete pillars with different types of reinforcement. These are the pillars simulating parts of walls that can, for example, form in the precast wall of residential buildings after an opening has been carved. The pillars are variously reinforced: from the simple reinforcement with wire mesh to the reinforcement with standard reinforcement bars. Behavior of the pillars, that have been subjected to two types of experiments in the past, is verified by software for non-linear analysis for concrete structures. Depending on the types of loading, the ultimate limit state, deformation and stress state of the individual pillars are studied.

Abstract: The scheme for the wave strain strengthening of inner cylindrical surfaces diameter up to 100 – 120 mm is offered. One-ring and multi-ring drifts, bolls of various diameters are used as a tool. The effectiveness of a dynamic influence upon the center of deformation is considerably higher than that of the static one used during common burninshing. At the same time the share of power spent for the plastic deformation increases and power intensity drops, and technological possibilities of the process become wider. The experimental research of wave deformation strengthening at different diameters of openings in bushes with different wall thickness revealed that the process is realized in a wide range of tightnesses from 0.5 to 3 mm which is necessary to choose taking into account the wall thickness, and strengthening embraces the whole wall thickness (up to 20 mm) under certain conditions. A considerable decrease of roughness height parameters of the strengthened surface and profile bearing length increase are established. The formation of oil pockets takes place on a surface worked as a consequence of kinematic peculiarities of the wave strain strengthening that contributes to wear resistance increase of friction couples. The productivity of wave strain strengthening exceeds the productivity of common burnishing more than twice, and there appears a possibility to exclude the operations of finishing abrasion with unfavorable technological heredity from the engineering procedure.

Abstract: In truss-steel plate shear wall (SPSW) structures, the main role of SPSW is to provide horizontal and vertical stiffness for the system, which requires the SPSW capable of adapting to bi-directional loading. In order to satisfy the goal, stiffeners need to be added to the SPSW. In addition, openings are usually set within the SPSWs to meet certain architecture or utilization needs. Stiffener design criteria for such SPSW with or without opening are first derived according to the principle of yielding before buckling and local buckling before overall buckling. Then the deduced stiffener design criteria are compared with the current design codes. Finally the stiffener design recommendations are proposed for SPSW with or without opening adapting to bi-directional loading.

Abstract: Recirculation region behind a fume cupboard sash is the potential contributor to the leakage of the contaminants due to its large size. This is found from the computational fluid dynamics (CFD) simulation of SERVCO fume cupboard using κ-ω turbulence model. For a good fume cupboard, the recirculation zone needs to be minimized while maintaining the flow distribution to all area in the fume cupboard. The opening on the baffle may reduce the recirculation zone which in turn may reduce back flow that is the cause of leakage. In this paper, the effect of shape of baffle openings on flow distributions of a SERVCO fume cupboard will be presented as a result of CFD. The results are presented in terms of velocity vectors Vy (in the direction towards the sash opening) at different cross sections for 4 opening shapes. The opening is found to improve the airflow distribution.

Abstract: In order to determine the pipeline characteristics of the sand-wind simulation system, using the closed wind tunnel system, the partial loss of the fan’s pre-axial guide device was obtained from experiments at different openings. The partial loss of the axial guide device was simulated at different boundary conditions with FLUENT [1]. The simulation and experiment results were compared and a plan of setting reasonable boundary conditions was confirmed. A feasible method of using numerical simulation to predict the characteristics of dusty weather simulation pipeline system was developed.

Abstract: In the modern building construction, different size of openings are provided in the web of reinforced concrete (RC) deep beams to accommodate utility pipes and ducts of essential services such as electricity cable, telephone network and air-conditioning network. However, accommodation of such openings caused reduction in beam strength, stiffness and caused excessive cracking and deflection. Many investigations were conducted to study the behaviour of openings in beams and relevant strengthening options to reinstate the lost capacity. One of the strengthening options considered lamination of fiber reinforced polymer (FRP) sheets due to its superior properties such as high tensile strength and stiffness, high resistance to corrosion, excellent fatigue performance and good resistance to chemical attack. FRP lamination has been widely accepted by the research community and practicing engineers in the construction industry as the material for strengthening and rehabilitation of common problems. However, quite limited literatures contained the use of FRP to strengthen RC deep beams with openings. This paper discussed the review of eleven different articles contained study of RC deep beams with openings together with effects of strengthening using FRP sheets. The outcome of this review paper outlined the way forward and future research focus in this area.

Abstract: In order to meet the requirements for using function of structure, openings are often needed to be laid out in shear wall, and the mechanical behaviors of the wall will be significantly influenced. The experimental analysis, establishment of simplified mechanical model and numerical simulation researches on shear wall with opening were reviewed, the research findings on shear wall with opening at home and abroad were summarized, and the seismic behaviors were induced and analyzed. The problems about seismic behaviors of shear wall with opening which need to be solved urgently were pointed out.