Numerical Modeling of Reinforced Concrete Slabs under Impact Loading

2020 ◽  
Vol 857 ◽  
pp. 99-108
Author(s):  
Enas Mabrook Mouwainea ◽  
Abdul Muttalib I. Said
Keyword(s):  
Reinforced Concrete ◽  
Impact Force ◽  
Impact Load ◽  
Time History ◽  
Reinforcement Ratio ◽  
Concrete Slabs ◽  
Slab Thickness ◽  
Central Deflection ◽  
Reinforced Concrete Slabs ◽  
The Impact

This paper aims to provide a numerical model able to represent the behavior of reinforced concrete slabs subjected to impact loads. The nonlinear finite element analysis adopted by ABAQUS/Explicit Software was used in this study. A parametric study was conducted to provide a comprehensive understanding of the behavior of reinforced concrete slabs subjected to impact load. Two parameters were varied amongst the slabs which classified in to two groups. In the first groups, the thickness of slabs is variable, which was equal to (75, 100, 150 mm). In the second group, the thickness of the slab is constant and the variable was the reinforcement ratio, which ranged from (0.58 to 1%), per layer. In dynamic analysis, the load-time history and deflection-time relation were investigated. For the first group, obviously, as the slab thickness increased, the maximum central deflection of the slabs decreased by (48 – 84 %). Also, the impact force of the slabs increased by (40 – 106%) as the thickness of the slab increased by (33 – 100%). For the second group, the maximum central deflection of the slabs decreased by (6.6 – 8.8 %) as the steel reinforcement increased by (0.58 – 1 %). It was observed in the second group that the change in the value of the impact force was very limited. This lead to a fact that the impact force was not affected by the change of the reinforcement ratio, but mainly affected by the change of the slab thickness.

Finite Element Analysis of a Single-Layer Reticulated Dome under Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 327-331 ◽  
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Impact Force ◽  
Impact Load ◽  
Residual Deformation ◽  
Time History ◽  
Single Layer ◽  
Element Analysis ◽  
Deformation Stage ◽  
The Impact

Finite element model of both the single-layer Schwedler reticulated dome with the span of 50m and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. PLASTIC_KINEMATIC (MAT_003) material model which takes stain rate into account was used to simulate steel under impact load. The automatic point to surface contact (NODES TO SURFACE) was applied between the dome and impact block. Three stages of time history curve of the impact force on the apex of the single-layer Scheduler reticulated dome including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. It must be pointed out that the peak of the impact force of the single-layer reticulated dome increase with the increase of the weight and the velocity of the impact block, but the change of the velocity of the impact block is more sensitive than the change of weight of the impact block for the effect of the peak of the impact force, and a platform value of the impact force of the single-layer reticulated dome change near a certain value, and the duration time of the impact gradually increase. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of impact on the apex of the single-layer reticulated dome based on numerical analysis. Four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

Calculation of Ultimate Loads of Two-Way Reinforced Concrete Slabs

2012 ◽  
Vol 256-259 ◽  
pp. 850-854
Author(s):  
Yong Wang ◽  
Yu Li Dong
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Failure Criteria ◽  
Reinforcement Ratio ◽  
Concrete Slabs ◽  
Test Results ◽  
Simple Method ◽  
Simply Supported ◽  
Reinforced Concrete Slabs

This paper presents the latest developments of a simple method used to determine the ultimate load of two-way simply supported reinforced concrete slabs. Based on the reinforcement ratio, two failure criteria are proposed in the paper. The effectiveness of the developed model is validated through satisfactory comparison with from test results.

scholarly journals Experiment and Simulation Study on the Dynamic Response of RC Slab under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yue Wang ◽  
Jun Liu ◽  
Zhimin Xiao ◽  
Futian Zhao ◽  
Yi Cheng
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Impact Resistance ◽  
Great Influence ◽  
Time History ◽  
Reinforcement Ratio ◽  
Slab Thickness ◽  
Drop Hammer ◽  
Rc Slab ◽  
The Impact

Reinforced concrete (RC) slab is an important component in civil construction and protection engineering, and its dynamic response under impact loading is a complex mechanical problem, especially for two or multiple continuous impact loads. In this paper, a series of drop hammer impact tests were carried out to investigate the dynamic response of RC slabs with two successive impacts. The time history of impact force and the failure characteristic of the slab surface were recorded. Moreover, four influence factors, including slab thickness, reinforcement ratio, impact location, and drop hammer height have been discussed. Besides, a 3D numerical model based on the finite element method (FEM) was established to expand the research of constrained force, deflection, and vertical stress of an RC slab. The results show that increasing the slab thickness and reinforcement ratio can improve the impact resistance of an RC slab. The impact point location and drop hammer height have a great influence on the dynamic response of the RC slab. In addition, the RC slab will have more obvious damage under the second impact, but the dynamic response becomes weaker. It may be because of the local damage in the concrete caused by the first impact that would weaken the propagation of vibration.

scholarly journals Effect of Strengthening Methods on Two-Way Slab under Low-Velocity Impact Loading

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5603
Author(s):  
Sun-Jae Yoo ◽  
Tian-Feng Yuan ◽  
Se-Hee Hong ◽  
Young-Soo Yoon
Keyword(s):  
Reinforced Concrete ◽  
High Performance Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Low Velocity Impact ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
The Impact

In this study, the performance of reinforced concrete slabs strengthened using four methods was investigated under impact loads transferred from the top side to bottom side. The top and bottom sides of test slabs were strengthened by no-slump high-strength, high-ductility concrete (NSHSDC), fiber-reinforced-polymer (FRP) sheet, and sprayed FRP, respectively. The test results indicated that the test specimens strengthened with FRP series showed a 4% increase in reaction force and a decrease in deflection by more than 20% compared to the non-strengthened specimens. However, the specimen enhanced by the NSHSDC jacket at both the top and bottom sides exhibited the highest reaction force and energy dissipation as well as the above measurements because it contains two types of fibers in the NSHSDC. In addition, the weight loss rate was improved by approximately 0.12% for the NSHSDC specimen, which was the lowest among the specimens when measuring the weight before and after the impact load. Therefore, a linear relationship between the top and bottom strengthening of the NSHSDC and the impact resistance was confirmed, concluding that the NSHSDC is effective for impact resistance when the top and bottom sides are strengthened. The results of the analysis of the existing research show that the NSHSDC is considered to have high impact resistance, even though it has lower resistance than the steel fiber reinforced concrete and ultra-high-performance-concrete, it can be expected to further studies on strengthening of NSHSDC.

scholarly journals EVALUATING THE EFFECTIVE DESIGN OF REINFORCED CONCRETE FLOOR SLABS IN CIVIL WORKS IN TRA CU DISTRICT – TRA VINH PROVINCE

2020 ◽  
Vol 1 (35) ◽  
pp. 51-61
Author(s):  
Cong Thanh Nguyen ◽  
Nhung Hong Tu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Slab Thickness ◽  
Design Technique ◽  
Concrete Floor ◽  
Reinforced Concrete Slabs ◽  
Floor Slabs ◽  
Design Documents ◽  
Engineering Projects ◽  
Effective Design

This study was conducted to determine the effectiveness of the design of reinforced concrete slabs of several civil engineering projects in Tra Cu district – Tra Vinh province. Utilizing the design documents of 6 projects, these slabs were redesigned based on TCVN 5574 – 2018. The design results were compared with those provided in the design documents. The results show that most of the design in the provided documents was either greater than or equal to the end design studied: the slab thickness is from 0% - 20%, the steel percentage of the slabs are from 0% - 63,3%, and the concrete quantity is from 0% - 20%. In conclusion, it is recommended for engineers to select an optimal slab design technique in order to reduce dead loads, to provide a reasonablesteel percentage and still being capable of carrying loads, which will result in an effective design for the project.

scholarly journals Experimental research of the impact of upper reinforcement on the tension membrane action of narrow three-span reinforced concrete slabs

2020 ◽  
Vol 310 ◽  
pp. 00056
Author(s):  
Miroslaw Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Failure Mechanism ◽  
Experimental Research ◽  
Experimental Tests ◽  
Concrete Slabs ◽  
Membrane Action ◽  
Experimental Stand ◽  
Reinforced Concrete Slabs ◽  
Reinforced Steel ◽  
The Impact

The aim of the paper was to demonstrate the influence of reinforced steel parameters and quantity on the failure mechanism of four three-span models of reinforced concrete strips with the dimensions 7140×500×190 mm. Two models had only bottom reinforcement, while two were reinforced at the bottom and upper sides. The paper contains the description of the experimental stand and models along with the results of experimental tests which were compared with the results of the calculations based on traditional methods.

Study on the Impact Properties of a New Debris Flow Dam Based on Steel-Concrete Composite Structure

2014 ◽  
Vol 638-640 ◽  
pp. 2056-2059 ◽  
Author(s):  
Ya Xiong Liang ◽  
Xiu Li Wang ◽  
Chang Wu ◽  
Zhi Gang Lv
Keyword(s):  
Finite Element ◽  
Debris Flow ◽  
Impact Force ◽  
Impact Load ◽  
Weak Link ◽  
Time History ◽  
Type Model ◽  
Finite Element Software ◽  
New Type ◽  
The Impact

The impact force is one of the most weak link of the dynamics studies of debris flow for many years. To make the structure or components are better able to suffer the impact load such as debris flow, explosions, a new debris flow dam is designed by introducing this new type model with spring. It is simulated under boulder impact by using finite element software LS-DYNA.The stress distribution, impact and displacement time history curve under typical conditions are obtained. The results show that the resist impact effect of new debris flow dam is very obvious.

scholarly journals Experimental Research on the Mechanical Performance of the Bolted Rock under Lateral Impact Load: Effect of Prestress, Body Material, and Anchorage Style

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yongzheng Wu ◽  
Yukai Fu ◽  
Denyun Hao ◽  
Gangye Guo
Keyword(s):  
Axial Force ◽  
Impact Force ◽  
Impact Load ◽  
Impact Resistance ◽  
Time History ◽  
Full Length ◽  
Lateral Impact ◽  
Impact Peak ◽  
Action Time ◽  
The Impact

In order to reveal the impact mechanical properties and their key influencing factors of the bolted rock under the lateral impact load, through the lateral drop hammer impact test, the time-history curve of impact force, axial force of the bolt, and surface strain of the sample under different combination types of influencing factors is obtained, and the whole process of deformation and failure of the bolted rock is recorded. The test results show that the material of the bolt has a significant influence on the impact force and axial force of the bolt. There is a positive correlation between bolt strength and impact peak and impact attenuation slope and a negative correlation between bolt strength and impact action time. The effect of prestress on the impact resistance of the bolted rock was also evaluated by the test which suggested that prestress of the bolt can significantly reduce both impact time and bolt axial force of the bolted rock but has limited effect on the impact force. It was also found that the time-history curve of the impact force of anchoring rock mass had significant difference with full-length anchoring and nonanchoring. Compared with the nonanchoring bolt, the full-length anchored rock mass has a larger impact peak and shorter action time, which means that the impact resistance of the full-length bolted rock has a certain degree of weakening. Through scientific research, determining the reasonable bolt material, prestress value, and anchorage style can improve the impact resistance of the sample.

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