scholarly journals Numerical and Experimental Protective Performance Evaluation of Sacrificial Member Effects on the Protective Structures

2021 ◽  
Vol 1203 (3) ◽  
pp. 032074
Author(s):  
Jihye Kwon ◽  
Seungsu Han ◽  
Sungkon Kim
Keyword(s):  
Design Procedure ◽  
Back Surface ◽  
Wall Structure ◽  
Security Measures ◽  
Blast Pressure ◽  
Rc Structures ◽  
Blast Overpressure ◽  
Barrier Type ◽  
Protective Structures ◽  
Protective Performance

Abstract Principal objectives of the protective design are on protecting life, property, facility, system device and operations by developing protective design measures that reduce threat level and vulnerability while enhancing structural resilience. Protective design procedure against blast hazard would be accomplished with the threat identification, risk-based assessment, and designing the members and structures based on the proper design requirements. Considerable necessity before the protective design is to find out the various measures reducing the blast effect such as security measures, architectural configuration, and mitigation schemes without any structural strengthening the structure itself. This paper addresses the mitigation scheme to reduce the blast overpressure in general, and then a specific barrier type is introduced as sacrificial structures with the performance verification. The general schemes to reduce the blast pressure by installing barriers is mainly using RC type structures which have typical shapes and sizes. This barrier type has advantages both on installing easiness and cost. In the barrier type sacrificial wall structure, instead of using the normal RC structures, enhanced-cement concrete and composites are useful to improve protective performance and scabbing of the back surface of the RC walls. A series of the wall type RC barriers are modeled and fabricated to investigate and verify blast pressure migration and protective performance based on theoretical and numerical analysis.

Design optimization of hopper cars employing functionally graded honeycomb sandwich panels

2021 ◽  
pp. 095440972110496
Author(s):  
Ayman Al-Sukhon ◽  
Mostafa SA ElSayed
Keyword(s):  
Design Optimization ◽  
Sandwich Panels ◽  
Design Procedure ◽  
Functionally Graded ◽  
Sandwich Composite ◽  
Wall Structure ◽  
Concentrate Mass ◽  
Cross Sectional ◽  
Baseline Design ◽  
Honeycomb Sandwich

In this paper, a novel multiscale and multi-stage structural design optimization procedure is developed for the weight minimization of hopper cars. The procedure is tested under various loading conditions according to guidelines established by regulatory bodies, as well as a novel load case that considers fluid-structure interaction by means of explicit finite elements employing Smoothed Particle Hydrodynamics. The first stage in the design procedure involves topology optimization whereby optimal beam locations are determined within the design space of the hopper car wall structure. This is followed by cross-sectional sizing of the frame to concentrate mass in critical regions of the hopper car. In the second stage, hexagonal honeycomb sandwich panels are considered in lower load regions, and are optimized by means of Multiscale Design Optimization (MSDO). The MSDO drew upon the Kreisselmeier–Steinhausser equations to calculate a penalized cost function for the mass and compliance of a hopper car Finite Element Model (FEM) at the mesoscale. For each iteration in the MSDO, the FEM was updated with homogenized sandwich composite properties according to four design variables of interest at the microscale. A cost penalty is summed with the base cost by comparing results of the FEM with the imposed constraints. Efficacy of the novel design methodology is compared according to a baseline design employing conventional materials. By invoking the proposed methodology in a case study, it is demonstrated that a mass savings as high as 16.36% can be yielded for a single hopper car, which translates into a reduction in greenhouse gas emissions of 13.09% per car based on available literature.

Simulating the Response of Composite Reinforced Floor Slabs Subjected to Blast Loading

2003 ◽  
Author(s):  
Darell Lawver ◽  
Raymond Daddazio ◽  
Gwang Jin Oh ◽  
C. K. B. Lee ◽  
Allan B. Pifko ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Terrorist Attack ◽  
Structural Response ◽  
High Strength ◽  
Reinforcing Bars ◽  
Blast Pressure ◽  
Floor Slab ◽  
Blast Overpressure ◽  
Floor Slabs ◽  
Tensile Forces

The threat of terrorist attack against civil infrastructure in the US and other countries has led to the need to better understand the response of structures and structural components to an impulsive air blast overpressure. One scenario that is present in many cities is delivery trucks entering basement or street level loading/unloading areas. A bomb present in one of these delivery trucks could cause considerable damage to the floor slab (and consequently the building) above the blast by causing a vertical uplift, a condition that the slab was not designed to resist. Traditional methods to retrofit floor slabs to resist an upwards blast pressure require that additional tension sustaining reinforcing bars (rebars) be placed near the slab upper surface. This reinforcing method is costly, difficult to produce, and adds additional weight to the overall structure in building retrofit situations. Another approach to reinforcing the slab is to bond light-weight, high strength fiber composite material to the slab upper surface as a means of resisting the tensile forces from the slab upward motion. This paper presents results from an effort to simulate the response of a reinforced concrete floor slab with a fiber composite retrofit subjected to a blast overpressure. The simulations were performed using the Weidlinger Associates’ FLEX [1] finite element code for structural response calculations. The MAZ [2] computational fluid dynamics code was used to generate blast pressure. This paper will discuss the modeling effort used to predict the response of fiber composite retrofitted slabs and compare the computational analysis to test results1.

Numerical study for impact resistant design of full scale arch type reinforced concrete structures under falling weight impact test

2011 ◽  
Vol 18 (9) ◽  
pp. 1275-1283 ◽  
Author(s):  
Abdul Qadir Bhatti ◽  
Shameem Khatoon ◽  
Aamir Mehmood ◽  
Abid Dastgir ◽  
Norimitsu Kishi
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Impact Test ◽  
Design Procedure ◽  
Full Scale ◽  
Analysis Method ◽  
Rc Structures ◽  
Weight Impact ◽  
Current Impact ◽  
Falling Weight

In this paper, a falling-weight impact test using full scale arch type reinforced concrete (RC) structures was conducted to verify a proposed impact response analysis method. The applicability of the numerical analysis method was confirmed by comparison with the experimental results. The validity of the current impact resistant design procedure to the performance based design procedure was investigated using the proposed numerical analysis method. From this study, it is confirmed that by applying the current impact resistant design procedure, a performance based impact resistant design with a sufficient safety margin may be obtained for the full scale arch type RC structures.

Comparative Study on the Earthquake Behavior of Frame-Shear Wall Structure of Concrete Filled Steel Tubular under Conventional Earthquake

2011 ◽  
Vol 368-373 ◽  
pp. 1981-1984
Author(s):  
Xiang Tao Xu ◽  
Xiao Hu
Keyword(s):  
Reinforced Concrete ◽  
Comparative Study ◽  
Seismic Behavior ◽  
Shear Wall ◽  
Structure Design ◽  
Wall Structure ◽  
Dynamic Behaviors ◽  
Rc Structures ◽  
Earthquake Resistant ◽  
Calculation Results

In this paper, seismic behavior of the frame-shear wall structure, which are respectively composed of the concrete filled steel tubular (CFST) and of the reinforced concrete (RC) column, have been studied under the conventional earthquake. Dynamic behaviors and earthquake responses including deformation and forcing of the CFST and RC structures are analyzed. Comparing the calculation results, the earthquake resistant behavior of the CFST structure has been evaluated synthetically, which may be referential for structure design.

scholarly journals Numerical Analysis of Dynamic Force Acting Perpendicularly on a Wall Made of Concrete Blocks with Rubber Inserts

2016 ◽  
Vol 16 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Maciej Major ◽  
Izabela Major
Keyword(s):  
Numerical Analysis ◽  
Back Surface ◽  
Wall Structure ◽  
Dynamic Force ◽  
Structure Model ◽  
Concrete Blocks

Abstract In this paper numerical analysis considering the influence of dynamical force acting on wall made of concrete blocks with rubber inserts is presented. By examining the stress values on front and back surface of the analysed wall structure model, the effectiveness of proposed solution can be measured comparing to the wall made of concrete blocks without rubber inserts. Complete numerical analysis was performed in ADINA program.

scholarly journals Thermal Protective Performance of Aerogel Embedded Firefighter's Protective Clothing

2013 ◽  
Vol 8 (2) ◽  
pp. 155892501300800 ◽  
Author(s):  
Zhengkun Qi ◽  
Dongmei Huang ◽  
Song He ◽  
Hui Yang ◽  
Yin Hu ◽  
...  
Keyword(s):  
Human Body ◽  
Infrared Radiation ◽  
Protective Clothing ◽  
Temperature Jump ◽  
Heat Exposure ◽  
Back Surface ◽  
Thermal Protective Performance ◽  
Adequate Level ◽  
Protective Performance ◽  
Ir Light

Firefighters’ protective clothing (FPC) is a four-component ensemble that protects the human body against the following properties: a. radiation; b. flashover conditions; c. puncture and abrasion hazards; while still maintaining an adequate level of dexterity and comfort. Therefore, the thermal protective performance (TPP) of FPC is very important. Generally, FPC with higher TPP will result in fewer injuries. In this study, aerogel is proposed to be used in FPC to improve its TPP, and the feasibility is examined. The results show that the temperature on the back surface of the FPC samples that were filled with aerogel was 100 °C lower than that of those unfilled FPC samples under the same heat exposure. However, a short temperature jump occurred during the tests due to the penetration of infrared radiation (IR) light. In addition, the weight of the FPC sample in which the aerogel was embedded was lessened about 24.3%. It is concluded that filling aerogel in FPC can effectively improve its TPP and lessen its weight, while some additives must be used to absorb or scatter the IR light that causes the temperature jump.

Intensity-Reduced Design for Structure with Fluid Viscous Dampers

2014 ◽  
Vol 638-640 ◽  
pp. 1818-1821
Author(s):  
Da Hai Zhao ◽  
Li Li Tong ◽  
Yong Qi Chen ◽  
Zhen Qiang Zhang
Keyword(s):  
Design Procedure ◽  
Dynamic Responses ◽  
Wall Structure ◽  
Analysis Model ◽  
Base Shear ◽  
Reinforced Concrete Frame ◽  
Viscous Dampers ◽  
Concrete Frame ◽  
Fluid Viscous Dampers ◽  
Story Drift

The intensity-reduced method based on fluid viscous dampers is proposed in this study. The analysis model of fluid viscous dampers is firstly introduced. The intensity-reduced design procedure is thoroughly discussed. Taking an 11-story reinforced concrete frame shear-wall structure as example, the intensity-reduced method is implemented in this study. The dynamic responses of the structure with and without fluid viscous dampers, including the maximum inter-story drift angle, base shear force, are discussed. The results show that the proposed intensity-reduced method for structure with fluid viscous dampers is feasible, and the responses of structure satisfy the code for seismic design of buildings. The earthquake input energy is mainly dissipated by fluid viscous dampers, which guarantees the safety of the main structure.

RIGID-PLASTIC SEISMIC DESIGN OF REINFORCED CONCRETE SHEAR WALL

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5740-5746
Author(s):  
CHANG LIN FAN ◽  
SHAN YUAN ZHANG
Keyword(s):  
Seismic Design ◽  
Linear Time ◽  
Response Spectrum ◽  
Plastic Hinge ◽  
Design Procedure ◽  
Time History ◽  
Shear Wall ◽  
Wall Structure ◽  
Collapse Mechanism ◽  
Rigid Plastic

Basing the displacement-capacity design method and capacity spectrum method, a new rigid-plastic seismic design procedure is proposed to describe the behavior of shear wall structure under strong earthquakes. Firstly the concept of rigid-plastic hinge is used to choose a collapse mechanism of shear wall, then according to the dynamic performance criterion the yield load of structure is determined through rigid-plastic response spectrum. This procedure is used in 11-story reinforced structure shear wall design, the results of comparison with refined Non-Linear Time-History Analysis showing good agreement.

scholarly journals STRUKTUR DINDING PELINDUNG LERENG DENGAN METODE KAKI BELALANG TIRUAN

Teras Jurnal ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 11
Author(s):  
Sulardi Sulardi
Keyword(s):  
Research Method ◽  
Flood Control ◽  
Retaining Wall ◽  
Point Contact ◽  
Wall Structure ◽  
Success Story ◽  
Ground Anchors ◽  
Drainage Channels ◽  
The Stability ◽  
Protective Structures

<p class="11daftarpustaka">Tujuan penelitian adalah untuik memberikan gambaran tentang spesifikasi, bentuk, dimensi dan konfigurasi struktur dinding pelindung tanah dengan metode kaki belalang serta metode pelaksanaannya di lapangan. Metode penelitian ini menggunakan metode penelitian terpakai dan penelitian ini sekaligus sebagai technical notes success story aplikasi struktur pelindung lereng dengan metode kaki belalang tiruan pada pembangunan reservoir pengendali banjir di kota Balikpapan. Hasil penelitian menunjukan, metode kerja pemasangan struktur dinding pelindung lereng dengan metode kaki belalang tiruan dapat diaplikasikan dengan baik dan aman tanpa terjadi incident. Stabilitas dinding penahan lereng ini terletak pada penggunaan pondasi jenis paku dibagian bawah, pasangan tapak-tapak penumpu dinding pelindung lereng, ground anchor dan pasangan saluran drainase.      </p><p class="11daftarpustaka"> </p><p class="11daftarpustaka">Kata kunci:<em> dinding pelindung lereng, kaki belalang, three point contact.</em><em></em></p><p><em> </em></p><p><em> </em></p><p align="center"><strong>Abstract</strong></p><p class="11daftarpustaka"> </p><p>The research objective is to provide an overview of the specifications, shape, dimensions and configuration of the structure of the protective walls of the land with the method of grasshopper and its method of implementation in the field. This research method used the used research method and this study as well as a technical notes success story application of slope protective structures with artificial grasshopper foot method in the construction of flood control reservoirs in the city of Balikpapan. The results showed that the working method of the installation of a slope protective wall structure with artificial grasshopper foot method can be applied properly and safely without incident. The stability of the slope retaining wall lies in the use of nail type foundations at the bottom, pairs of tread supporting walls, ground anchors and pair of drainage channels.</p><p> </p><p>Keywords: <em>protective slope walls, grasshopper feet, three point contact.</em><em></em></p>

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