Background to seismic design provisions in CSA A23.3–04 for high-strength concrete

2009 ◽  
Vol 36 (4) ◽  
pp. 565-579 ◽  
Author(s):  
Patrick Paultre ◽  
Denis Mitchell
Keyword(s):  
Compressive Strength ◽  
Seismic Design ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
Concrete Structures ◽  
High Strength ◽  
Frame Structure ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Loading Tests

This paper presents the background experimental and analytical research that was carried out to develop the provisions for the seismic design of high-strength concrete structures in the 2004 Canadian standard CSA A23.3–04. It is noted that the 1994 Canadian standard CSA A23.3–94 limited the concrete compressive strength to 55 MPa for the seismic design of nominally ductile and ductile structures, while the 1995 New Zealand Standard limited the concrete compressive strength to 70 MPa. In contrast, the 2008 American Concrete Institute (ACI) code ACI 318M has no upper limit on concrete strength, even for the seismic design of ductile structural elements. This tremendous variation in these limits indicated that more experimental evidence was needed. This paper presents experimental results of reversed cyclic loading tests on large-scale structural components as well as simulated seismic loading tests of a frame structure constructed with high-strength concrete. The goal of this collaborative research program at the University of Sherbrooke and McGill University was to determine the seismic design and detailing requirements for high-strength concrete structures to achieve the desired level of ductility and energy dissipation. The experimental programs include full-scale testing of the following: columns subjected to a pure axial load (square and circular columns); columns subjected to flexure and axial loads; beam-column subassemblages (square and circular columns); coupling beams in coupled wall structures; shear walls and a two-storey, three-dimensional frame structure. The results of the responses of the high-strength concrete structural specimens are compared with the responses of companion specimens constructed with normal-strength concrete.

scholarly journals BEHAVIOUR OF HIGH-STRENGTH CONCRETE CIRCULAR COLUMNS CONFINED BY HIGH-STRENGTH SPIRALS UNDER CONCENTRIC COMPRESSION

2020 ◽  
Vol 26 (6) ◽  
pp. 564-578
Author(s):  
Chongchi Hou ◽  
Wenzhong Zheng ◽  
Wei Chang
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Proposed Model ◽  
High Strength Concrete Columns

This paper tested the behaviour of 32 high-strength concrete columns confined by high-strength spirals under concentric compression. The test parameters included unconfined concrete compressive strength, spiral yield strength, volumetric ratio, and spiral spacing. The results showed that bulging and shear sliding were the two characteristic types of failure patterns of the thirty-two confined columns, depending on spiral spacing and concrete strength. Moreover, the spiral in most specimens did not yield at the confined concrete compressive strength. An analytical confinement model for high-strength concrete columns confined by high-strength spirals was proposed. In this proposed model, the calculated value of the spiral stress at the confined concrete compressive strength was used to calculate the feature points of the stressstrain curve. The proposed model showed good correlations with available experimental results of 64 columns.

Performance of Rubberized High Strength Concrete after Fire

2010 ◽  
Vol 163-167 ◽  
pp. 1403-1408
Author(s):  
Feng Liu ◽  
Gui Xuan Chen ◽  
Li Juan Li
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Test Results ◽  
Rubber Powder ◽  
Strength Concrete ◽  
Spalling Failure ◽  
Powder Content ◽  
Small Content

The effects of recycled rubber powder on working abilities, density and compressive strength of high strength concrete (HSC) at room temperature were studied in this paper. The characteristics of rubberized high strength concrete (RHSC) after fire was investigated by surface observation, weight loss and retained strength testing. The sieve number of rubber powder used in test is No.40 (420μm), No.60 (250µm) and No.80 (178µm), and the content of rubber powder filled in RHSC is 1%, 2%, 3% and 4% with respect to cementation material respectively. Test results show that the increase in rubber powder content reduces the concrete strength, while the decrease in compressive strength of RHSC is less than 10% when the content of rubber powder is within 2%. RHSC with small content of rubber (1%) can restrain the spalling failure of concrete under high temperature.

Analysis of Post-Combustion High-Strength Concrete Compressive Strength Using Polypropylene Fibers

2020 ◽  
Vol 26 (1) ◽  
pp. 118-127
Author(s):  
Teuku Budi Aulia ◽  
Muttaqin Muttaqin ◽  
Mochammad Afifuddin ◽  
Zahra Amalia
Keyword(s):  
Compressive Strength ◽  
Thermal Stress ◽  
Silica Fume ◽  
High Temperatures ◽  
High Strength Concrete ◽  
High Strength ◽  
Polypropylene Fibers ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Maximum Value

High-strength concrete is vulnerable to high temperatures due to its high density. The use of polypropylene fibers could prevent structure explosion by forming canals due to melted fibers during fire, thus release its thermal stress. This study aims to determine the effect of polypropylene fibers on compressive strength of high-strength concrete after combustion at 400ºC for five hours. High-strength concrete was made by w/c-ratio 0.3 with cement amount 550 kg/m3 and added with silica fume 8% and superplasticizer 4% by cement weight. The variations of polypropylene fibers were 0%, 0.2% and 0.4% of concrete volume. The compression test was carried out on standard cylinders Ø15/30 cm of combustion and without combustion specimens at 7 and 28 days. The results showed that compressive strength of high-strength concretes without using polypropylene fibers decreased in post-combustion compared with specimens without combustion, i.e., 0.81% at 7 days and 23.42% at 28 days. Conversely, the use of polypropylene fibers can increase post-combustion compressive strength with a maximum value resulted in adding 0.2% which are 25.52% and 10.44% at 7 and 28 days respectively. It can be concluded that the use of polypropylene fibers is effective to prevent reduction of high-strength concrete compressive strength that are burned at high temperatures.

The Modulus of Elasticity of High-Strength Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 233-237 ◽  
Author(s):  
Zhao Hui Lu ◽  
Zhi Wu Yu ◽  
Yan Gang Zhao
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Empirical Model ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Plain Concrete ◽  
Strength Concrete ◽  
Wide Range

The paper discusses the modulus of elasticity of plain concrete for a wide range of compressive strength. A large volume of selected experimental data has been collected from existing literature and then analyzed. Particular emphasis has been given to studying the effects of concrete compressive strength and the type of coarse aggregate on the modulus of elasticity of plain concrete. The adequacy and applicability of the existing models for predicting the modulus of elasticity of high-strength concrete has been critically examined, and a new empirical model is proposed to cover concrete strength up to 125 MPa. The new empirical model seems to perform much better when applied to the published experimental data on normal weight concrete over a wide strength range.

Strain of High-Strength Concrete at Peak Compressive Strength

2012 ◽  
Vol 446-449 ◽  
pp. 161-165 ◽  
Author(s):  
Zhao Hui Lu ◽  
Yan Gang Zhao ◽  
Zhi Wu Yu
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Empirical Model ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Normal Weight ◽  
Strength Concrete ◽  
Normal Weight Concrete ◽  
Wide Range

The paper discusses the strain of high-strength concrete (HSC) at peak compressive strength for a wide range of compressive strength. A large volume of selected experimental data has been collected from existing literature and then analyzed. Particular emphasis has been given to studying the effects of concrete compressive strength and the types of coarse aggregate on the strain of HSC at peak compressive strength. The adequacy and applicability of the existing models for predicting the strain of HSC at peak compressive strength has been critically examined, and a new empirical model is proposed to cover concrete strength up to 125 MPa. The new empirical model seems to perform much better when applied to the published experimental data on normal weight concrete over a wide strength range.

Fatigue Investigation of High-Strength Concrete Members Reinforced with CFRP

2011 ◽  
Vol 250-253 ◽  
pp. 2202-2205
Author(s):  
Hong Hai ◽  
Li Sun ◽  
Ying Hua Zhao
Keyword(s):  
Fatigue Strength ◽  
High Strength Concrete ◽  
Low Cycle Fatigue ◽  
Concrete Strength ◽  
Concrete Structures ◽  
High Strength ◽  
Fatigue Performance ◽  
Plate Interface ◽  
Strength Concrete ◽  
Shear Fatigue

Fatigue damage becomes an emerging problem in lots of concrete structures which will subject to cyclic loadings during their working life. This paper presents a study on interfacial shear fatigue performance of a high-strength concrete structure strengthened by carbon fiber-reinforced plastic (CFRP) plate, which has been established as an effective method for rehabilitation and strengthening of concrete structures. Based on the static test, a new experimental investigation of the shear fatigue performance along the concrete-plate interface under the low cycle fatigue load in the condition of R=0.1 is presented. The main variable is the concrete strength. Compared with the static ultimate strength, fatigue strength decreases. Therefore, a safety factor of the fatigue strength at the interface of CFRP and concrete should be applied in design.

scholarly journals Influence of Different Drying Conditions on High Strength Concrete Compressive Strength

10.14311/228 ◽  
2001 ◽  
Vol 41 (3) ◽  
Author(s):  
M. Safan ◽  
A. Kohoutková
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Development ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Development Rates ◽  
Drying Conditions

The influence of different drying conditions on the compressive strength and strength development rates of high strength concrete up to an age of 28 days was evaluated. Two HSC mixes with and without silica fume addition were used to cast cubes of 10 cm size. The cubes were stored in different drying conditions until the age of testing at 3, 7, 28 days.

Behavior of Tension Splices for Reinforcing Bars Embedded in High-Strength Concrete

1998 ◽  
Vol 1624 (1) ◽  
pp. 125-131
Author(s):  
Atorod Azizinamini
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Building Code ◽  
Reinforcing Bars ◽  
Concrete Compressive Strength ◽  
Two Phase ◽  
Tension Development ◽  
Strength Concrete ◽  
The Impact

Safety concerns and a lack of test data on bond capacity of deformed reinforcing bars embedded in high-strength concrete (HSC) have been reasons that the American Concrete Institute (ACI) 318 building code has imposed an arbitrary limitation of 69 MPa (10,000 psi) in the calculation of tension development and splice lengths. This limitation was first introduced in the 1989 revision of the ACI 318 building code. In an attempt to evaluate the impact of this limitation and develop provisions for its removal, a two-phase investigation was carried out at the University of Nebraska-Lincoln. During both phases of the investigation, 70 beam splices were tested. The parameters studied included diameter, length, and deformation type of the reinforcing bars; amount of transverse reinforcement over the splice length; casting position; and concrete compressive strength. Results of the investigation are used to discuss the differences that exist between normal concrete and HSC, develop hypotheses to explain these observed differences, and suggest alternatives for removal of the current concrete compressive strength limitations existing in the ACI 318 building code for calculating tension development and splice lengths.

scholarly journals Assessment of Strength Development at Hardened Stage on High-Strength Concrete Using NDT

2020 ◽  
Vol 10 (18) ◽  
pp. 6261
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee ◽  
Hyeonggil Choi
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Temperature History ◽  
Strength Development ◽  
Strength Concrete

This study proposes model formulae for predicting the strength of concrete by analyzing the relationships between the results of nondestructive testing (NDT) methods and the compressive strength of concrete specimens at the hardened stage. Further, NDT of concrete molds and mock-up specimens was conducted using NDT methods (rebound hammer, ultrasonic pulse velocity). The water/cement (W/C) ratios were set to 0.48, 0.41, and 0.33 to achieve concrete strengths within the compressive strength range of 24–60 MPa. The evaluation parameters included the fresh concrete properties, compressive strength (mold and core), temperature history, maturity, rebound value, and ultrasonic pulse velocity. Evaluation results indicated that the reliability of existing models, based on the rebound and ultrasonic pulse velocity, is significantly low on high-strength concrete of 40 MPa or higher, and cannot satisfy the ±20% error range. Consequently, this study proposes a regression equation of the concrete strength based on the experimental rebound and ultrasonic pulse velocity values in a 24–60 MPa range, which offers satisfactory reliability.

Sign in / Sign up

Export Citation Format

Share Document