An Experimental Study on Hybrid Noncompression CF Bracing and GF Sheet Wrapping Reinforcement Method to Restore Damaged RC Structures

Abstract

We describe a novel technique for restoration of reinforced concrete (RC) structures that have sustained damage during an earthquake. The reinforcement scheme described here is a hybrid seismic retrofitting technique that combines noncompression X-bracing using CF with externally bonded GF sheets to strengthen RC structures that have sustained damage following an earthquake. The GF sheet is used to improve the ductility of columns, and the noncompression CF X-bracing system, which consists of CF bracing and anchors to replace the conventional steel bracing and bolt connections, is used to increase the lateral strength of the framing system. We report seismic restoration capacity, which enables reuse of the damaged RC frames via the hybrid CF X-bracing and GF sheet wrapping system. Cyclic loading tests were carried out to investigate hysteresis of the lateral load-drift relations, as well as the ductility. The GF sheet significantly improved the ductility of columns, resulting in a change in failure mode. The strengthening effect of conventional CF sheets used in columns is not sufficient with respect to lateral strength and stiffness. However, this study results in a significant increase in the strength of the structure due to the use of CF X-bracing and inhibited buckling failure of the bracing. This result can be exploited to develop guidelines for the application of the reinforcement system to restore damaged RC structures.

Дослідження Пошкоджених Залізобетонних Елементів, Основні Методи Їх Відновлення Та Підсилення

“…Їх використання поза межам експлуатаційного проектованого терміну часто визначається ступенем їх фактичного зносу, визначеного за результатами натурних обстежень і оцінки фактичного напружено-деформованого стану елементів. В таких ситуаціях надзвичайно важливим постає питання моделювання поведінки залізобетонної конструкції в умовах негативних силових і несилових впливів, прогнозування розвитку пошкоджень і зміни напружено-деформованого стану елемента, що було досліджено в значній кількості наукових досліджень в цій галузі ( [2,3,4]).…”

An Analytical Investigation of a Building Having Soft Storey Irregularity Strengthened With Concentrically Steel Braces

“…Concentrically Steel Braces (CSB) are utilized in order to meet the lateral load in steel buildings in the earthquake regulations. Although CSBs are not usually used in reinforced concrete buildings, it is still utilized in some cases as strengthening elements (Ju et al, 2014;Lee, 2015;Mowrtage, 2013;Unal and Kaltakci, 2016;Varum et al, 2013;Ebadi et al, 2018;Javadi and Yamakawa, 2019;Liu et al, 2019;Mashhadiali and Kheyroddin, 2018;Mazza et al, 2018;Oinam and Sahoo, 2018).…”

Pseudodynamic Testing of Buildings Retrofitted with External Steel Reinforced Concrete Frames to Increase Lateral Strength for Earthquake Damage Prevention

“…Over the past three decades, rehabilitation procedures for existing RC buildings have been promoted, leading to the development of several seismic strengthening techniques to improve their seismic performance [5][6][7][8][9]. ese methods include techniques to improve ultimate strength or deformation capability, as well as technology for vibration control.…”