Experimental evaluation of RC frames retrofitted by steel jacket, X-brace and X-brace having ductile ring as a structural fuse

Kheyroddin, Ali; Sepahrad, Reza; Saljoughian, Mohammad; Kafi, Mohammad Ali

doi:10.1007/s41024-019-0050-z

Cited by 17 publications

(7 citation statements)

References 15 publications

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“…Due to the attached form of the steel jacket to the frame members, to prevent slippage and stress focus at the connection zone with concrete surfaces, it was assumed that there is perfect contact and connection between them. Furthermore, experimental observations on the retrofitted RC joints by this paper authors illustrate that the slippage of steel jacket on concrete surfaces can be ignored [2,7]. According to the contents, the results will be categorized and presented in three sections, including the type of RC frame, the gusset plate's dimensions and the brace cross-section area.…”

Section: Parametric Studymentioning

confidence: 97%

“…In 1992, Pincheira and Jirsa [5] evaluated the resistance and seismic response of RC buildings strengthened with ductile steel braces and noted the stability and wideness of hysteresis loops of this type of composite frame. From 2000, Kheyroddin et al [6][7][8][9][10] have conducted several experimental and theoretical studies on the behaviour of RC frames strengthened by X, concentric, eccentric and buckling restrained steel braces, with and without the use of steel jackets and formable elements. In 2003, Maheri et al conducted experimental studies on X and knee-braced RC buildings to evaluate seismic parameters and the possibility of designing connections between braces and frames [11][12][13][14].…”

Section: Past Studiesmentioning

confidence: 99%

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Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

Sadeghinezhad

Kheyroddin

Mortezaei

2021

Period. Polytech. Civil Eng.

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Non-ductile reinforced concrete frames are commonly found in older buildings in many parts of the world. These structures designed for gravity loads, have limited lateral strength and ductility, are prone to excessive one-way lateral movement and soft-story mechanism. This paper focuses on the retrofit of an existing reinforced concrete frame, using steel X-braces by direct internal connection method. The main purpose is the analytical study of general behavior and response of large scale vulnerable frames. An experimental study was used to validate the numerical modeling performed in ABAQUS. Next the base samples were retrofitted with X-braces and four proposed direct internal connection methods. Furthermore, in a separate parametric studies, the effect of frame type, bracing cross-section dimensions and gusset plate shape were investigated. The results indicated that the stiffness, bearing capacity and absorbed energy of the reinforced concrete frame by using steel X-braces increases up to 4, 2.3 and 1.5 times, respectively. Moreover, bracing acts like the first defense system against lateral loads, such as structural fuse with its yield, increases the amount of energy dissipation. It also removes the plastic hinges by reducing the ultimate displacement and stress of lateral load in the panel zone.

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Section: Parametric Studymentioning

confidence: 97%

Section: Past Studiesmentioning

confidence: 99%

Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

Sadeghinezhad

Kheyroddin

Mortezaei

2021

Period. Polytech. Civil Eng.

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“…Many kinds of research in regards to the retrofitting of RC structures with steel elements have been done [16][17][18][19][20][21][22]. In these investigations, the effect of adding new elements such as the steel shear wall and different kinds of braces on the stiffness and ultimate strength of the frame were evaluated.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Retrofit of RC Frames Using TADAS Yielding Dampers

TahamouliRoudsari¹,

Cheraghi²,

Aghayari³

2022

Structural Durability &Amp; Health Monitoring

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TADAS dampers are a type of passive structural control system used in the seismic design or retrofitting of structures. These types of dampers are designed so that they would yield before the main components of the structure during earthquake. This dissipates a large portion of the earthquake's energy and reduces the energy dissipation demand in the main components of the structure. Considering its suitable performance, this damper has been the subject of numerous studies. However, there are still ambiguities regarding the effect of the number of these dampers on the retrofitting of reinforced concrete (RC) frames and their design procedure. In this study, a singlestory, single-bay RC frame with the scale of 1:3, equipped with the TADAS damper, was subjected to hysteresis loading until the drift of 4%. Then, for further assessment, 48 calibrated numerical models were constructed in ABAQUS and the effects of the number of TADAS dampers and column axial force upon the stiffness, strength, and ductility of the frame were accurately investigated. Also, a number of formulations were presented to calculate how the stiffness and lateral strength of the retrofitted frame are affected by an increase in the number of the TADAS plates. The results showed that if the shear capacity of the retrofitted frame is three times that of the initial frame, the structure would have the best response. In addition, if the axial force in the columns exceeds 0.2 P cr the energy dissipation and ductility factor of the frame drastically decrease.

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“…Changes in structure occupancy require strengthening with increasing bearing capacity of their members [1][2][3]. The strengthening method's choice depends on strength, amount of damage, type of members and connections, access to materials, and economic aspects [4,5]. These methods can include methods such as changing the lateral-resisting system (brace or shear wall), adding steel plates (steel jacket), using concrete jackets, using reinforced polymer fiber, using fiber concrete, shotcrete, and using near-surface mounted composite rebars, etc.…”

Section: Introductionmentioning

confidence: 99%

Strengthening of RC Beams Using SCC Jacket Consisting of Glass Fiber and Fiber-Silica Fume Composite Gel

Mohsenzadeh

Maleki

Lotfollahi-Yaghin

2021

IJE

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In this paper, strengthening of RC beams with self-consolodating concrete (SCC) jacket containing glass fiber (GF) and fiber-silica fume composite gel (FSCG) were investigated. FSCG can use as a substitute for a part of the cement that contains silica fume powder, polypropylene fibers, superplasticizer, concrete waterproof, and some other admixtures. In order to evaluate the performance of the proposed jacket, twelve beams were strengthened and a control beam was made. The variables included the amount of glass fibers consumed in the jacket (0, 0.25, 0.5, 0.75, 1 and 1.25% by volume) and the amount of FSCG gel (0 and 7%), respectively. Fresh and hardened concrete properties and flexural capacity of RC beams were investigated. The use of FSCG in RC jackets can compensate well for the deficiency in strength due to the GF entry into the concrete matrix. High affinity of these materials improve the cohesion between cement and GFs. RC jackets containing GF and FSCG increased the beams' energy absorption capacity by about 89 to 463%, depending on the percentages of GFs. RC jacket containing GF and FSCG delays the growth of the primary crack and it can significantly increase the maximum load. Also, Glass Fiber Reinforced Polymer (GFRP) sheets have poor performance compared to the proposed method due to separation from the surface of the strengthened beams, and their load-bearing capacity and energy absorption are lower.

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Experimental evaluation of RC frames retrofitted by steel jacket, X-brace and X-brace having ductile ring as a structural fuse

Cited by 17 publications

References 15 publications

Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

Investigating the Retrofit of RC Frames Using TADAS Yielding Dampers

Strengthening of RC Beams Using SCC Jacket Consisting of Glass Fiber and Fiber-Silica Fume Composite Gel

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