Although the ductility energy ratio ($$\mu_{E}$$ μ E ) of the reinforced concrete beam has been the topic of numerous study purposes and critical inquiry for the last decades, narrow consideration, especially in terms of reinforced concrete deep beams (RCDBs), is conducted to examine the ductility energy of hybrid-RC deep beams with various CFRP configurations. Growing the ductility of RCDB by CFRP reinforcement is significant in terms of shear resistance. Therefore, the objective herein is to explore the consequence of CFRP configurations (full side warped, 45° and 90° side stripes) on the ductility energy of RCDBs per two values of the shear span over depth proportion ($$a/d$$ a / d ) of 1.0 and 1.75, and shear reinforcement ratios ($$\rho_{v}$$ ρ v ) of 0.0% and 0.4%. The experimental testing program included 12 RCDBs, three ordinaries (unstrengthen), and nine retrofitted with several CFRP configurations. The results show that the CFRP strengthened beams is presented a higher degree of increase in terms of mid-span deflection with respect to conventional beams. The ductility energy index ($$\mu_{E}$$ μ E ) increases with the increase of the shear reinforcement ratio ($$\rho_{v}$$ ρ v ). The dissipated energy demonstrated by strengthening beam with CFRP is from 45 to 80%, and it was higher than those of reference RCDBs. The energy absorption of RCDBs is improved due to the attendance of CFRP configurations of about 15% and 51% for $$a/d$$ a / d proportion of 1.0 and 1.75, respectively, and for $$\rho_{v}$$ ρ v of 0% and 0.4% are about 15% and 86% consecutively.
Towers are important structures for installing radio equipment to emit electromagnetic waves that allow radio, television and/or mobile communications to function. Feasibility, cost, and speed of the construction are considered in the design process as well as providing stability and functionality for the communication tower. This study proposes the new design for construction of segmental tubular section communication tower with ultra-high-performance fibre concrete (UHPFC) material and prestress tendon to gain durability, ductility, and strength. The proposed mix design for UHPFC in this study which used for construction of communication tower is consisted of densified Silica Fume, Silica fine and coarse Sand and hooked-ends Steel Fiber. The prestressed tendon is used in the tower body to provide sufficient strength against the lateral load. The proposed design allows the tower to be built with three precast segments that are connected using bolts and nuts. This paper presents a novel method of construction and installation of the communication tower. The advantages of proposed design and construction process include rapid casting of the precast segment for the tower and efficient installation of segments in the project. The use of UHPFC material with high strength and prestress tendon can reduce the size and thickness of the tower as well as the cost of construction. Notably, this material can also facilitate the construction and installation procedure.
Within the last decades, the needed for communication towers has accelerated with the requirements for effective communication, especially for radio, radar, and television. The complexity configuration of the tower and limit access to the structure body especially inner part of the tower with hollow section is led the health monitoring of tower as the main challenging issue to maintenance during its function. The change of natural frequencies can be considered as one of the prevalent damage detection methods in structural assessment procedures. Therefore, the main aim of present research is to develop health monitoring system for Ultra High Fiber Performance Reinforced Concrete (UHPFRC) communication tower based on frequency domain response. Since the frequency data of tower is mostly noisy and interpreting of frequency in different modes in variant case of tower damage. The hybrid algorithm based on the Adaboost, Bagging and RUSBoost algorithms are implemented to identify the damage in the UHPFRC communication tower using frequency domain data. The training samples for the algorithm are obtained from a finite element simulation and full-scale experiment testing is also performed to generate the testing samples. The finite element simulation dynamic frequency results are verified through conducting a full-scale experimental test on 30 m height UHPFRC communication tower. For this propose, frequency Response Functions (FRF’s), for healthy and damaged structures were obtained by exciting of tower by an impact hammer and the acceleration response recorded by three accelerometers sensors attached in suitable positions. The developed hybrid algorithm to identifying the damage is tested and verified by considering the part of tower segments 2–3 and conducting experimental testing on the healthy structure as well as a damaged structure which caused using dynamic actuator. The testing results proved the accuracy of the developed optimized hybrid algorithm to identify damage in the tower structure in variant condition.
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