Evaluation of internal blast resistance of bi-directionally prestressed concrete tubular structure according to ANFO explosive charge weight

2021 ◽  
Author(s):  
Ji-Hun Choi ◽  
Seung-Jai Choi ◽  
Tae-Hee Lee ◽  
Dal-Hun Yang ◽  
Jang-Ho Jay Kim
Keyword(s):  
Prestressed Concrete ◽  
Explosive Charge ◽  
Blast Resistance ◽  
Crack Pattern ◽  
Structural Behavior ◽  
Charge Weight ◽  
Property Damage ◽  
Blast Pressure ◽  
Prestressing Loss ◽  
Real Scale

When extreme loading from an internal is applied to prestressed concrete (PSC) structures, serious property damage and human casualties may occur. However, existing designs for PSC structures such as prestressed concrete containment vessels (PCCV) do not include features to protect the structure from the blasts. Therefore, the internal blast resistance capacity of PSC structures is evaluated by internal blast tests on bi-directional PSC tubular members. The goal of the study was to obtain the structural behavior data from an internal detonation. The ANFO charges were detonated at the center of the mid-span of the tube specimen with a standoff distance of 1,000 mm. The data acquired included blast pressure, deflection, strain, crack pattern, and prestressing loss. The data are used derive the equations to calculate the required internal blast charge weight to fail a real-scale PCCV and to calibrate a commercial simulation program to be used for internal blast simulations.

scholarly journals Structural Behavior of Precast Lightweight Foam Concrete Sandwich Panel with Double Shear Truss Connectors under Flexural Load

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Noridah Mohamad ◽  
A. I. Khalil ◽  
A. A. Abdul Samad ◽  
W. I. Goh
Keyword(s):  
Compressive Strength ◽  
Sandwich Panel ◽  
Crack Pattern ◽  
Structural Behavior ◽  
Foam Concrete ◽  
Structural Behaviour ◽  
Shear Connectors ◽  
Double Shear ◽  
Partially Composite ◽  
Lightweight Foam

This paper presents the structural behaviour of precast lightweight foam concrete sandwich panel (PFLP) under flexure, studied experimentally and theoretically. Four (4) full scale specimens with a double shear steel connector of 6 mm diameter and steel reinforcement of 9 mm diameter were cast and tested. The panel’s structural behavior was studied in the context of its ultimate flexure load, crack pattern, load-deflection profile, and efficiency of shear connectors. Results showed that the ultimate flexure load obtained from the experiment is influenced by the panel’s compressive strength and thickness. The crack pattern recorded in each panel showed the emergence of initial cracks at the midspan which later spread toward the left and right zones of the slab. The theoretical ultimate load for fully composite and noncomposite panels was obtained from the classical equations. All panel specimens were found to behave in a partially composite manner. Panels PLFP-3 and PLFP-4 with higher compressive strength and total thickness managed to obtain a higher degree of compositeness which is 30 and 32.6 percent, respectively.

scholarly journals Optimal Localization of Smart Aggregate Sensor for Concrete Damage Monitoring in PSC Anchorage Zone

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6337
Author(s):  
Quang-Quang Pham ◽  
Ngoc-Loi Dang ◽  
Quoc-Bao Ta ◽  
Jeong-Tae Kim
Keyword(s):  
Damage Detection ◽  
Prestressed Concrete ◽  
Impedance Model ◽  
Artificial Damage ◽  
Smart Aggregate ◽  
Damage Monitoring ◽  
Concrete Damage ◽  
Potential Damage ◽  
Optimal Localization ◽  
Real Scale

This study investigates the feasibility of smart aggregate (SA) sensors and their optimal locations for impedance-based damage monitoring in prestressed concrete (PSC) anchorage zones. Firstly, numerical stress analyses are performed on the PSC anchorage zone to determine the location of potential damage that is induced by prestressing forces. Secondly, a simplified impedance model is briefly described for the SA sensor in the anchorage. Thirdly, numerical impedance analyses are performed to explore the sensitivities of a few SA sensors in the anchorage zone under the variation of prestressing forces and under the occurrence of artificial damage events. Finally, a real-scale PSC anchorage zone is experimentally examined to evaluate the optimal localization of the SA sensor for concrete damage detection. Impedance responses measured under a series of prestressing forces are statistically quantified to estimate the performance of damage monitoring via the SA sensor in the PSC anchorage.

scholarly journals Assessment of Mechanical Properties of Corroded Prestressing Strands

2020 ◽  
Vol 10 (12) ◽  
pp. 4055 ◽  
Author(s):  
Chi-Ho Jeon ◽  
Cuong Duy Nguyen ◽  
Chang-Su Shim
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Prestressed Concrete ◽  
Critical Issue ◽  
Concrete Bridges ◽  
Structural Behavior ◽  
Maximum Deformation ◽  
Prestressing Steel ◽  
External Tendons ◽  
Governing Factor

The corrosion of prestressing steel in prestressed concrete bridges is a critical issue for bridge maintenance. To assess structures with corroded strands, it is necessary to define the mechanical properties of the strands and their influence on the structural behavior. In this study, corroded strands were taken from external tendons in existing post-tensioned concrete bridges and tested to determine the effects of corrosion on their tensile properties. Empirical equations for the tensile strength and ductility of the corroded strands were proposed using test results. The most corroded wire governs the mechanical properties of the strand. Experiments on prestressed concrete beams with a single corroded strand were conducted to investigate their structural behavior. A reduction in the flexural strength and maximum deformation was observed in these experiments. According to the section loss of a wire in a strand and its location in a beam, the flexural capacity can be evaluated using the proposed equation. The reduced ultimate strain of the corroded strand can be the governing factor of the flexural strength.

scholarly journals Structural Behavior of Concrete Beams Containing Recycled Coarse Aggregates under Flexure

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
In-Hwan Yang ◽  
Jihun Park ◽  
Kyoung-Chul Kim ◽  
Hyungbae Lee
Keyword(s):  
Experimental Data ◽  
Flexural Strength ◽  
Concrete Beams ◽  
Crack Pattern ◽  
Crack Spacing ◽  
Experimental Results ◽  
Structural Behavior ◽  
Experimental Program ◽  
Coarse Aggregates

The structural behavior of concrete beams containing recycled coarse aggregates (RCAs) was investigated in this study using detailed experimental data. Twelve concrete beams were tested in the experimental program: nine beams with varying RCA contents and three control beams with natural coarse aggregates (NCAs). The parameters for investigating the structural behavior of the RCA concrete beams under flexure were the RCA content (30%, 50%, and 100%) and tensile rebar ratio (0.50%, 0.79%, and 1.14%). The crack pattern of the RCA beams was similar to that of the NCA beams; however, the RCA beams exhibited smaller crack spacing than the NCA beams. The flexural strength was slightly affected by the RCA content. However, the ductility of the beam was not significantly influenced by the RCA content. A comparison of the experimental results and the calculations from the ACI 318 and EC 2 provisions for the flexural strength showed that the current provisions conservatively predicted the flexural strength of the RCA concrete beams.

Procedure Inversion Effect Analysis of Final System Transformation of Prestressed Concrete Continuous Girder Bridge

2014 ◽  
Vol 501-504 ◽  
pp. 1323-1327
Author(s):  
Xu Luo ◽  
Lu Rong Cai
Keyword(s):  
Stress Distribution ◽  
Prestressed Concrete ◽  
Steel Beams ◽  
System Transformation ◽  
Box Girder ◽  
Pull Out ◽  
Temporary Support ◽  
Continuous Girder Bridge ◽  
Girder Bridge ◽  
Prestressing Loss

When the cantilever construction is adopted by the prestressed concrete continuous girder bridge, the order of two key procedures between removing temporary support and tensing remanent prestressed cable is used to be ignored. In order to study the influence of procedure inversion, the influences on bridge shape, stress distribution and prestressing loss were calculated for one common prestressed continuous concrete box girder bridge by MIDAS CIVIL 2006, respectively. The obtained result presents that: the influence on the bridge shape and the prestressing loss are not apparent, but the influence on the stress distribution is serious; the maximal compressive stress of procedure inversion is more 42.3% than common construction procedure only by tensing the remaining steel beams at box girder; especially, the combining area between the box girder and temporary support is easy to pull out. So, the procedure inversion construction method cant be accepted.

scholarly journals Experimental Study on the Damage Characteristics of Polymer Slabs Subjected to Air Contact and Close-In Explosions

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhidong Liu ◽  
Xiaohua Zhao ◽  
Hongyuan Fang ◽  
Xueming Du ◽  
Binghan Xue ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shock Wave ◽  
Failure Mode ◽  
Explosive Charge ◽  
Time History ◽  
Dynamic Mechanical Properties ◽  
Charge Weight ◽  
Pressure Time ◽  
Static Mechanical ◽  
Air Explosion

As a new antiseepage reinforcement material, polyurethane grouting material has been widely studied in terms of its static mechanical properties. However, research on its dynamic mechanical properties is relatively rare. In this research, considering the influence of the explosive charge weight, the air contact and close-in explosion experiments of polymer slabs were carried out. The failure mode and damage spatial distribution characteristics of polymer slabs were explored. Pressure time history curve of air shock wave was obtained using an air shock wave tester. The influence of polymer slabs on the propagation of air explosion shock wave was compared and analyzed. The results show that, under the air contact explosion, the polymer slab mainly suffers local damage, while under close-in explosion, overall damage is the main damage mode. With the increase of the explosive charge weight, the failure mode of the polymer slab transits from surface crack and slight spalling to local and whole crushing.

Effect of holes and segmentation on the structural behavior of a prestressed concrete girder

2014 ◽  
Vol 18 (6) ◽  
pp. 1711-1719 ◽  
Author(s):  
Man-Yop Han ◽  
Kyung-Seok Jin ◽  
Dong-Hak Chang ◽  
Tae-Heon Kang ◽  
Se-Jin Jeon
Keyword(s):  
Prestressed Concrete ◽  
Structural Behavior ◽  
Concrete Girder
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