scholarly journals Structural behaviour of reinforced high performance concrete frames subjected to monotonic lateral loading.

Author(s):  
Ali Ehsani Yeganeh

This thesis describes the structural performance of reinforced one storey flexural and shear-critical frames made of high performance concretes (HPCs) such as: self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) subjected to monotonic lateral loading. The performance of SCC/ECC/UHPC frames are described based on load-deformation/moment-rotation responses, stiffness, strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. The experimentally obtained moment and shear capacities of the frames are compared with those obtained from Codes and other existing design specifications. Overall, ECC frames showed better performance in terms of higher energy absorbing capacity and ductility compared to SCC/UHPC frames. ECC/UHPC frames showed higher load carrying capacity compared to SCC frames. ECC and UHPC shear-critical frames without shear reinforcement were able to prevent shear failure due to fiber bridging and crack control characteristics contributing to the enhanced shear resistance of the matrix.

2021 ◽  
Author(s):  
Ali Ehsani Yeganeh

This thesis describes the structural performance of reinforced one storey flexural and shear-critical frames made of high performance concretes (HPCs) such as: self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) subjected to monotonic lateral loading. The performance of SCC/ECC/UHPC frames are described based on load-deformation/moment-rotation responses, stiffness, strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. The experimentally obtained moment and shear capacities of the frames are compared with those obtained from Codes and other existing design specifications. Overall, ECC frames showed better performance in terms of higher energy absorbing capacity and ductility compared to SCC/UHPC frames. ECC/UHPC frames showed higher load carrying capacity compared to SCC frames. ECC and UHPC shear-critical frames without shear reinforcement were able to prevent shear failure due to fiber bridging and crack control characteristics contributing to the enhanced shear resistance of the matrix.


2021 ◽  
Author(s):  
Haile Mengistu

Composite slabs with profiled steel deck and concrete toping have gained wide acceptance as they lead to faster, lighter and economical construction. Extensive research works have been conducted on the behaviour of composite slabs to study their structural behavior and steel-concrete interface shear bond resistance which primarily governs the failure. However, the use of emerging highly durable engineered cementitous composite (ECC) in composite slab is new and no research has been conducted yet. High strain hardening and intrinsic crack width characteristics of ECC can significantly improve structural performance of composite slabs through enhancing ductility, energy absorbing capacity and steel-concrete shear bond. In this study, experimental investigations are conducted to evaluate the shear bond characteristics of composite slabs made with ECC and conventional self-consolidating concrete (SCC) using Code based m-k method. Twelve slab specimens having variable shear span and two types of profiled steel deck were tested under four point loading. The performance of ECC and SCC composite slabs are compered based on load-deflection response, stress-strain development in concrete and steel, failure modes, energy absorbing capacity and steel-concrete shear bond parameters (m and k) and bond stress.


2021 ◽  
Author(s):  
Haile Mengistu

Composite slabs with profiled steel deck and concrete toping have gained wide acceptance as they lead to faster, lighter and economical construction. Extensive research works have been conducted on the behaviour of composite slabs to study their structural behavior and steel-concrete interface shear bond resistance which primarily governs the failure. However, the use of emerging highly durable engineered cementitous composite (ECC) in composite slab is new and no research has been conducted yet. High strain hardening and intrinsic crack width characteristics of ECC can significantly improve structural performance of composite slabs through enhancing ductility, energy absorbing capacity and steel-concrete shear bond. In this study, experimental investigations are conducted to evaluate the shear bond characteristics of composite slabs made with ECC and conventional self-consolidating concrete (SCC) using Code based m-k method. Twelve slab specimens having variable shear span and two types of profiled steel deck were tested under four point loading. The performance of ECC and SCC composite slabs are compered based on load-deflection response, stress-strain development in concrete and steel, failure modes, energy absorbing capacity and steel-concrete shear bond parameters (m and k) and bond stress.


Author(s):  
Yu Shen ◽  
Biao Ma ◽  
Ruilong Wang

<p>Accelerated bridge construction (ABC) has attracted substantial attentions around the world owing to advantages of minimizing construction delivery time, improving component material quality and promoting overall-economy performance. An essential factor in widespread and successful implementation of the ABC lies in the reliable connections between precast units. In this study, the distinction of seismic performance between the high and short precast reinforced concrete pier columns with a new column-to-footing (or cap beam) connection filled with ultra-high performance concrete (UHPC) were experimentally investigated through the quasi-static testing. Based on the observations of test results, although the phenomena of sliding and uplifting around the joints were obvious, the failure modes of high and short columns were the flexural failure and the shear failure on the non-joint zone, respectively. Moreover, the damage process, the ductility capacity, the resilience behavior and the hysteresis energy response of the two large-scaled prefabricated piers were described and discussed.</p>


2021 ◽  
Vol 16 (2-3) ◽  
pp. 61-74
Author(s):  
Sahar Ghasemi ◽  
Amir Mirmiran ◽  
Yulin Xiao ◽  
Kevin Mackie

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ankang Liu ◽  
Bing Wang ◽  
Fei Li

Purpose This paper aims to study the effect of elevated temperature on the compression behaviour of carbon fibre polyphenylene sulphide (CF/PPS) laminates notched and unnotched specimens made by film stacking method (FSM). Design/methodology/approach The surface of CF was coated with a silane coupling agent to form an effective transition layer with PPS, so as to enhance the interfacial interaction between CF and PPS. Considering the influence of fabrication pressure, forming temperature and cooling rate on the properties of laminates to obtain a reasonable preparation process. Conducting a compressive experiment of notched and unnotched specimens at different temperatures, which failure modes were examined by scanning electron microscope and stereo microscope. Findings The experimental observations highlight that with the increase of temperature, the transition failure mode from fibre broken to kink-band appeared in unnotched specimens, which were closely attributed to the matrix state. The notched specimens appeared more complex failure mode, which can be attributed to the joint effect of temperature and opening hole. Research implications A simple way of FSM for composite material laminates has been developed by using woven CF and PPS films. Originality/value The outcome of this study will help to understand the compression response mechanism of composite materials made by FSM at different temperature.


2020 ◽  
Vol 10 (2) ◽  
pp. 153-164
Author(s):  
Hui Zheng ◽  
Dongdong Zhou ◽  
Xinfeng Yin ◽  
Lei Wang

Ultra-high-performance concrete (UHPC) material, a new type of cement-based composite material, is usually employed in the bridge engineering. The transfer and anchorage length of steel strand in UHPC material is different from that in ordinary concrete; nevertheless, few design standards are found that how to anchor the transfer and anchoring length of steel strand in UHPC material under normal curing. Through central pull-out test under the different conditions of protective layer thickness and embedded length, the load-slip curves, failure modes, and bond strength of 36 UHPC material specimens under normal curing were studied. The experimental results showed that the ultimate bond stress between UHPC material and steel strand under natural curing conditions is 7.01∼11.68 MPa. When the compressive strength of cube was 157 MPa; the bond strength under natural curing was smaller than that under thermal curing; when the thickness of the protective layer of steel strand with a diameter of 15.2 mm is greater than 30 mm, it had a little influence on bond strength. The regression analysis of the test results based on the experimental results proves that the recommended formulas for the design of transfer length and anchorage length of steel strand in UHPC material were in great agreement with the results of published studies.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Shilong Peng ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Xiaojian Wang ◽  
Mingjing Li ◽  
...  

As coal resources must be mined from ever deeper seams, high-strength, high-performance concrete shaft linings are required to resist the load of the soil surrounding the deep freezing well. In order to determine the optimal concrete mix for the unique conditions experienced by such high-strength high-performance reinforced concrete shaft lining (HSHPRCSL) structures in deep freezing wells, an experimental evaluation of scaled HSHPRCSL models was conducted using hydraulic pressure load tests. It was observed that as the specimens ruptured, plastic bending of the circumferential reinforcement occurred along the failure surface, generated by compression-shear failure. These tests determined that HSHPRCSL capacity was most affected by the ultimate concrete uniaxial compressive strength and the thickness-diameter ratio and least affected by the reinforcement ratio. The experimental results were then used to derive fitting equations, which were compared with the results of theoretical expressions derived using the three-parameter strength criterion for the ultimate bearing capacity, stress, radius, and load in the elastic and plastic zones. The proposed theoretical equations yielded results within 8% of the experimentally fitted results. Finally, the finite element analysis method is used to verify the abovementioned results, and all errors are less than 12%, demonstrating reliability for use as a theoretical design basis for deep HSHPRCSL structures.


2005 ◽  
Vol 32 (6) ◽  
pp. 1103-1113 ◽  
Author(s):  
M Lachemi ◽  
K M.A Hossain ◽  
V Lambros

Self-consolidating concrete (SCC) is a new generation of high performance concrete known for its excellent deformability and high resistance to segregation and bleeding. Lack of information regarding in situ properties and structural performance of SCC is one of the main barriers to its acceptance in the construction industry. There is some concern among researchers and designers that SCC may not be strong enough in shear because of some uncertainties in mechanisms resisting shear — notably the aggregate interlock mechanism. Because of the presence of comparatively smaller amount of coarse aggregates in SCC, the fracture planes are relatively smooth as compared with normal concrete (NC) that may reduce the shear resistance of concrete by reducing the aggregate interlock between the fracture surfaces. The paper compares the shear resistance of SCC and NC based on the results of an experimental investigation on 18 flexurally reinforced beams without shear reinforcements. The test parameters include concrete type, maximum size of coarse aggregate, coarse aggregate content, and beam shear span-to-depth ratio. Shear strength, shear ductility, crack patterns, and failure modes of all experimental beams are compared to analyze the shear resistance mechanisms of SCC and NC beams in both pre- and post-cracking stages. The recommendations of this paper can be of special interest to designers considering the use of SCC in structural applications.Key words: self-consolidating concrete, shear resistance, shear resistance factor, aggregate interlock, dowel action.


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