A Simplified Two-Step Approach for the Seismic Retrofitting Design of Existing Structures Towards a Resiliency Enhancement

2021 ◽  
pp. 133-146
Author(s):  
Rafael Shehu
Keyword(s):  
Seismic Retrofitting ◽  
Existing Structures ◽  
Resiliency Enhancement

TRIAL CONSTRUCTION FOR SEISMIC RETROFIT BY CFT BRACE ON AN ISOLATED ISLAND

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyuki Nakahara ◽  
Yukiko Ashida
Keyword(s):  
Low Cost ◽  
Seismic Retrofit ◽  
Seismic Retrofitting ◽  
Load Carrying Capacity ◽  
Loading Test ◽  
Existing Structures ◽  
Heavy Equipment ◽  
Load Carrying ◽  
Rc Building ◽  
Set Up

The authors have been developing a seismic retrofitting method using concrete-filled steel tubular (CFT) members as a diagonal brace. The features of the method are easy set-up and low-cost because we made the enforcing devices lightweight and a simple connecting method to the existing structures. This method provides many advantages for the buildings located at the places where are difficult to transport heavy materials and equipment. An experimental construction for the seismic retrofit was conducted at the 2-story RC building on an isolated island in Japan. The construction was succeeded by only three persons in two days without heavy equipment. This paper is consisted of the reports of the constructing process and the loading test of the connecting part of the method. The trial construction includes a new detail of the connection. Two specimens were made and tested to estimate the lateral load carrying capacity of the connection.

scholarly journals Seismic Retrofitting Solutions for Precast RC Industrial Buildings Struck by the 2012 Earthquakes in Northern Italy

2021 ◽  
Vol 7 ◽  
Author(s):  
Fabio Minghini ◽  
Nerio Tullini
Keyword(s):  
Fragility Curves ◽  
Seismic Retrofitting ◽  
Rc Structures ◽  
Existing Structures ◽  
The North ◽  
Industrial Buildings ◽  
Precast Buildings ◽  
Damage Data ◽  
Emilia Romagna Region ◽  
Cladding Panels

In 2012, the North of Italy was hit by a seismic sequence characterized by two main events occurred on May 20 and 29 with MW = 6.1 and 6.0, respectively. Those earthquakes were particularly severe toward precast Reinforced Concrete (RC) structures not designed for seismic resistance. In the past years, the authors implemented a database collecting damage data and typological information on the industrial buildings struck by the Emilia earthquakes. That database was used to develop empirical fragility curves, which highlighted the considerable vulnerability of precast buildings conceived in accordance with pre-seismic code provisions. More recently, the interventions of seismic retrofitting on the same buildings, funded by the Emilia-Romagna region and designed by engineers which were directly hired by the companies, were examined in detail and critically revisited. A selection of these interventions is presented in this paper, which analyzes the effectiveness of the various retrofitting solutions, with a specific attention to the force transfer mechanisms between existing structures and strengthening systems. The interventions are divided between column strengthening (based, for example, on RC or steel jacketing) and interventions aimed at providing the building with a suitable earthquake resistant system (based, for example, on either the use of the existing cladding panels or the implementation of new bracing systems). Graphical representations of the analyzed solutions with the relevant construction details are provided.

scholarly journals Experimental and Analytical Study on Torsional Behaviour Of RC Flanged Beams Strengthened With Glass FRP

2019 ◽  
pp. 361-368
Author(s):  
K. Gowthami ◽  
D. Mohammed Rafi ◽  
K. Mohammed Rasheed
Keyword(s):  
Cross Sections ◽  
Construction Materials ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Seismic Retrofitting ◽  
Analytical Models ◽  
Experimental Result ◽  
Existing Structures ◽  
Torsional Behavior ◽  
T Beam

Environmental degradation, increased service loads, reduced capacity due to aging, degradation owing to poor construction materials and workmanships and conditional need for seismic retrofitting have demanded the necessity for repair and rehabilitation of existing structures. Fibre reinforced polymers has been used successfully in many such applications for reasons like low weight, high strength and durability. Many previous research works on torsional strengthening were focused on solid rectangular RC beams with different strip layouts and different types of fibres. Various analytical models were developed to predict torsional behavior of strengthened rectangular beams and successfully used for validation of the experimental works. But literature on torsional strengthening of RC T- beam is limited. In the present work experimental study was conducted in order to have a better understanding the behavior of torsional strengthening of solid RC flanged T-beams. An RC T-beam is analyzed and designed for torsion like an RC rectangular beam; the effect of concrete on flange is neglected by codes. In the present study effect of flange part in resisting torsion is studied by changing flange width of controlled beams_ The other parameters studied are strengthening configurations and fiber orientations. The objective of present study is to evaluate the effectiveness of the use of epoxy-bonded GFRP fabrics as external transverse reinforced to reinforced concrete beams with flanged cross sections (T-beam) subjected to torsion. Torsional results from strengthened beams are compared with the experimental result of the control beams without FRP application. The study shows remarkable improvement in torsional behavior of all the GFRP strengthen beams. The experimentally obtained results are validated with analytical model presented by A.Deifalla and A. Ghobarah and found in good agreement.

scholarly journals Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2184
Author(s):  
Takahiro Matsui ◽  
Kohei Suzuki ◽  
Sota Sato ◽  
Yuki Kubokawa ◽  
Daiki Nakamoto ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Carbon Fiber ◽  
Axial Stress ◽  
Steel Structures ◽  
High Strength ◽  
Seismic Retrofitting ◽  
Gusset Plates ◽  
Stepped Surfaces ◽  
Existing Structures ◽  
Stepped Surface

In recent years, many seismic retrofitting methods have been performed to improve the structural performance and prevent the brittle failure of structural members. In the case of steel structures, slender seismic braces have been widely used for buildings, towers, and bridges. The brace connections should resist the full plastic axial tension load to ensure adequate plastic deformation performance for vibration energy absorption. However, certain connections do not satisfy these requirements. Recently, carbon fiber reinforced plastic (CFRP) has been used extensively to strengthen existing structures because of its high-strength, high elastic modulus, and light-weight characteristics. In this paper, we investigate the applicability of CFRP strengthening for brace connections and gusset plates with stepped surfaces using the vacuum-assisted resin transfer molding technique as a pilot demonstration. Stepped surfaces can be eliminated by using alternative CFRP layers to straighten the structural CFRP layers in order to effectively transfer the axial stress. Eventually, it is shown that CFRP strengthening can improve the connection strength and plastic deformation with 3% elongation, even if the CFRP is molded on the stepped surface.

scholarly journals The High-Performance Dissipating Frame (HPDF) System for the Seismic Strengthening of RC Existing Buildings

2021 ◽  
Vol 13 (4) ◽  
pp. 1864
Author(s):  
Vincenzo Manfredi ◽  
Giuseppe Santarsiero ◽  
Angelo Masi ◽  
Giuseppe Ventura
Keyword(s):  
High Performance ◽  
Design Procedure ◽  
Seismic Retrofitting ◽  
Existing Buildings ◽  
Sustainable Solutions ◽  
Seismic Rehabilitation ◽  
Existing Structures ◽  
Rc Frames ◽  
Frame System ◽  
Displacement Based

In Italy as well as in other earthquake-prone countries, the large number of existing buildings requiring seismic retrofitting calls for sustainable solutions able to reduce both costs and downtime. To this purpose, in this paper, the High-Performance Dissipating Frame system (HPDF), a new strengthening solution for the seismic rehabilitation of existing buildings, is presented. HPDF is based on external precast reinforced concrete (RC) frames rigidly connected to the existing structures and equipped with shear damper devices in order to provide high dissipation capacity. The proposed solution permits: (i) to increase sustainability through works made up from the outside without removing/demolishing infills/other non-structural components, (ii) rapid execution by adopting precast resisting members mutually restrained with steel connections, and (iii) effectiveness due to shear damper devices able to dissipate a large amount of shaking energy. In the paper, a displacement-based design procedure is proposed and applied to a numerical example.

scholarly journals Describe the process of retrofitting existing buildings and evaluate the effectiveness of it in improving the seismic performance of structures in earthquake-prone regions

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Chang Liu
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Seismic Performance ◽  
Seismic Activity ◽  
Seismic Retrofitting ◽  
Existing Buildings ◽  
Existing Structures ◽  
Soil Failure

At present, earthquakes are a serious problem for building. Severe damages and collapses of buildings were caused by earthquakes in different degrees.It is reported that there are more than 68,858 deaths and hundreds of billions RMB losses in the May 12, 2008 Great Wenchuan Earthquake(Wang, 2008). So, more attention should be paid to seismic technology. In order to face the challenges of earthquake on building, the seismic retrofitting was put forward, which“is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes”

Advanced Composite Panels for Seismic and Vibration Mitigation of Existing Structures

2006 ◽  
Vol 128 (4) ◽  
pp. 618-632 ◽  
Author(s):  
Amjad J. Aref ◽  
Woo-Young Jung
Keyword(s):  
Structural Damage ◽  
Experimental Studies ◽  
Seismic Retrofitting ◽  
Great Promise ◽  
Earthquake Excitation ◽  
Cyclic Shear ◽  
Existing Structures ◽  
Advanced Composite ◽  
Energy Mechanism ◽  
Constrained Damping

In this paper, a conceptual design, fabrication, and testing of advanced polymer matrix composite (PMC) infill system are addressed for seismic retrofitting of steel frames. Such a system is designed to have a multi-panel PMC infill system with passive energy mechanism. The basic configuration of this system is composed of two separate components—namely, an inner PMC sandwich panel and outer damping panels. The inner PMC sandwich infill consists of two fiber-reinforced polymer (FRP) laminates with Divincell® H core, and outer damping panels are made of FRP laminate plates and passive energy constrained damping layers—combining polymer honeycomb and 3M viscoelastic solid materials—at the interface between the laminates. The interactions of these two components produce considerable stiffness and enhanced damping properties in the structure following different drift level. Conceptually, the FRP outer damping panels are designed to produce the damping through the cyclic shear straining of the combined interface damping layers. Moreover, as the lateral drift increases, the inner PMC sandwich infill is designed to provide considerable lateral stiffness to resist severe earthquake excitation and avoid excessive relative floor displacements that cause both structural and non-structural damage. As part of this research, analytical and experimental studies were performed to investigate the effectiveness of the proposed multi-infill panel concept. The prefabricated multi-panel PMC infill holds a great promise for enhanced damping performance, simplification of the construction process, and the reduction of time and cost when used for seismic retrofitting applications.

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