Innovative connections for precast concrete moment resisting frames

2015 ◽  
Vol 48 (3) ◽  
pp. 204-221
Author(s):  
Farhad Behnamfar ◽  
Hadi Rafizadeh ◽  
Mortza Omidi
Keyword(s):  
Compressive Strength ◽  
Numerical Study ◽  
Precast Concrete ◽  
Research Work ◽  
Displacement Curve ◽  
Moment Connections ◽  
Moment Resisting ◽  
Compressive Strength Of Concrete ◽  
Design And Practice ◽  
Strength And Ductility

This research work presents new details for moment connections in precast concrete structures satisfying both design and practice criteria. In this paper the results of the numerical study on the connections are presented. For the analysis, the ANSYS software is selected because of its diversity in nonlinear analysis. By calculating the monotonic load-displacement curve of each connection, the connections are evaluated for their stiffness, strength, and ductility. The compressive strength of the connection concrete is taken to be 30, 35 and 40 MPa, for each round of analysis. The results of the analysis show that the proposed connections are stiff enough to be moment resisting and to be emulating an equivalent monolithic, or basic connection. It is illustrated that the connections are stronger but somewhat less ductile than the basic connection regardless of the concrete strengths examined. Moreover, it is shown that in each precast connection while increasing the compressive strength of concrete does not affect the connection stiffness considerably, it increases the ultimate load and ductility of the connection. As a main result of this study, the suggested connection details are categorized based on their stiffness, strength, and ductility. The suggested connections can be used in moment resisting precast concrete buildings based on the desired strength and ductility.

An innovative detail for precast concrete beam–column moment connections

1991 ◽  
Vol 18 (4) ◽  
pp. 690-710
Author(s):  
Hany Ahmed El-Ghazaly ◽  
Heyad Saud Al-Zamel
Keyword(s):  
Concrete Beam ◽  
Experimental Testing ◽  
Precast Concrete ◽  
Steel Frame ◽  
Reinforcing Bars ◽  
Shear Tests ◽  
Moment Connections ◽  
Modes Of Failure ◽  
Moment Resisting ◽  
Flexural Tests

A new detail is introduced for precast concrete beam-to-column moment connections. The detail consists of a connecting steel frame used to mechanically connect the threaded end protruding reinforcing bars from beam and column. The connection detail is made convenient to assemble where the erection method resembles that of steel construction. No idle crane time is necessary, since the connecting steel frame is designed to carry the beam's own weight. When the connection construction is completed, the joint functions as a moment resisting hard connection. The experimental testing program involved testing of twelve full-scale specimens in addition to a pilot test. Of the twelve tests seven are flexural tests, three are shear tests, and two are monolithic flexural tests for comparison. Modes of failure in the flexural tests were mainly due to rupture of tension reinforcement; however, premature slippage of the rebars may occur under certain conditions, but could be conveniently prevented. In the shear tests, diagonal tension crack failure predominated. If the connection parameters are properly selected, the connection will be capable of developing the beam's full plastic moment and undergo sufficient rotation before collapse. Key words: precast concrete, moment connections, connecting steel frame, stiffness, strength, ductility.

The Effect of Different Curing Conditions on Compressive Strength of Concrete

2017 ◽  
Vol 60 (3) ◽  
pp. 147-153
Author(s):  
Muhammad Arslan ◽  
Muhammad Asif Saleem ◽  
Maria Yaqub ◽  
Muhammad Saleem Khan
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Concrete Structures ◽  
Strength Test ◽  
The Other ◽  
Cylindrical Shape ◽  
Curing Conditions ◽  
Compressive Strength Test ◽  
Different Types ◽  
Compressive Strength Of Concrete

The focus of this research work was to analyse the effect of different types of curing oncompressive strength of concrete structures. For this purpose, 54 test specimens of cylindrical shape wereprepared. These specimens were cured with different methods and were tested on different age days toanalyse the effect of curing on compressive strength. Test specimens cured with conventional water curingmethod gives the highest results as compared to the other adopted methods.

scholarly journals Numerical Study of Circular Concrete Filled Steel Tubes Subjected to Pure Torsion

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 397
Author(s):  
Khanh Ba Le ◽  
Vui Van Cao
Keyword(s):  
Compressive Strength ◽  
Parametric Study ◽  
Numerical Study ◽  
Steel Tube ◽  
Torsional Moment ◽  
Pure Torsion ◽  
Steel Tubes ◽  
Moment Capacity ◽  
Compressive Strength Of Concrete ◽  
Concrete Filled Steel Tubes

This study numerically explored the torsional behavior of circular concrete-filled steel tubes (CFST) under pure torsion. Numerical models of CFSTs were developed in ABAQUS. The models were validated by comparing with the experimental results available in the literature; then, these models were used for parametric study. Based on the obtained results, the mechanism of torsional moment transferring from steel plates to CFST was presented. The results obtained from the parametric study indicated that the compressive strength of concrete marginally improved the torsional moment capacity of the CFST while concrete prevented buckling and helped the steel tubes to work more effectively. The steel strength significantly affected the torsional moment capacity of the CFST. When the yield strength of steel increased from 235 to 420 MPa, the yield torsional moment of the CFST increased by approximately 50%. The yield torsional moment capacity of the steel tube had the strongest correlation with the yield moment of the CFST, followed by the ratio of diameter to thickness of the steel tube while the parameters related to the compressive strength of concrete exhibited a poor correlation with the yield torsional moment.

scholarly journals Preliminary Studies of Ca-Al-Layered Double Hydroxide (Ldh) and Its Effect on the Compressive Strength in Concrete

2020 ◽  
pp. 131-151
Author(s):  
Archibong Ukeme Donatus ◽  
Ojeagah Kenneth ◽  
Michael Christopher Ukuegboho ◽  
I. E. Chiedu ◽  
Obasuyi Emmanuel Idemudia
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Load Test ◽  
Precipitation Method ◽  
Compressive Strength Test ◽  
Sem Micrograph ◽  
Compressive Strength Of Concrete ◽  
Co Precipitation ◽  
Double Hydroxide ◽  
Concrete Control

This research work involved the preliminary studies of CaAl-LDHs using co precipitation method and applying it in the preparation of concrete to evaluate the compressive strength in grade 15 concrete. Slum and compressive strength test were carried out on the concrete control and concrete mixed with CaAl-LDH, Scanning electron microscope (SEM) and X-Ray Diffractogram (XRD) was carried out on the synthesize LDH, concrete control, and concrete mixed with LDH. From the results obtained in the work failure load test, it was observed that there was an increase by 62.60% in the compressive strength of concrete mixed with 30kg of CaAl-LDHs, the SEM micrograph also shows the increase in the density and the less porosity of the concrete mixed with CaAl-LDH which explained the increase in the compressive strength of the concrete. CaAl-LDH has therefore shows a promising effect on the increase on the compressive strength of concrete.

scholarly journals Numerical Study Via Finite Element Analysis of the Structural Behavior of Rigid Pavement of Aerodromes

2020 ◽  
Vol 9 (1) ◽  
pp. 2-18
Author(s):  
Albert Willian Faria ◽  
Eduardo Matiola Souza ◽  
Rodrigo Alves E Silva
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Numerical Study ◽  
Concrete Slabs ◽  
Element Analysis ◽  
Rigid Pavement ◽  
Longitudinal Joints ◽  
Compressive Strength Of Concrete ◽  
3D Numerical Model ◽  
Pavement Thickness

The present study develops a 3D numerical model of the concrete pavement system of aerodromes in contact with the main landing gear of aircrafts using Finite Element Method (FEM). The pavement system used in the analysis consisted of six concrete slabs overlaying a subgrade medium with stiffness k. Doweled bars are considered for the pavement transverse joints while aggregate interlocks are considered for longitudinal joints. A parametric study was conducted to validate the model numerically, as well as to investigate the influence of the doweled bars, aggregate interlocks and subgrade stiffness on the pavement deflections when it is subjected to a dynamic load. About 77% decrease in deflection was attained due to the presence of doweled bars. This study additionally presents a methodology for designing the pavement thickness and the compressive strength of concrete based upon the Mohr-Coulomb’s failure criterion. It is found that for a pavement thickness of 0.305m the minimum compressive strength of concrete should be 28 MPa.

scholarly journals Stress-Strain Behavior of Steel Fiber-Reinforced Concrete Cylinders Spirally Confined with Steel Bars

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Bambang Sabariman ◽  
Agoes Soehardjono ◽  
Wisnumurti Wisnumurti ◽  
Ari Wibowo ◽  
Tavio Tavio
Keyword(s):  
Compressive Strength ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Confined Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Strain Behavior ◽  
Steel Bars ◽  
Concrete Cylinders ◽  
Compressive Strength Of Concrete ◽  
Strength And Ductility

The compressive strength of concrete according to certain codes can be based on the compressive strength of unconfined plain standard concrete cylinders tests at the age of 28 days. In this paper, the standard concrete cylinders were spirally confined with steel bars and with/without hooked-end steel fibers. The influence of the use of hooked-end steel fiber in spirally confined concrete with various pitches was investigated. It can be seen that the use of hooked-end steel fiber contributes significantly in improving both compressive strength and ductility of concrete. The compressive strength and ductility of steel fibered concrete also increase with the reduction of the spiral’s pitch.

scholarly journals Experimental and Numerical Study on a Proposed Moment-Resisting Connection for Precast Concrete Frames

2017 ◽  
Vol 0 (0) ◽  
pp. 0-0 ◽  
Author(s):  
Mojtaba Fathi ◽  
Mahdi Parvizi ◽  
Javad Karimi ◽  
M.Hossein Afreidoun
Keyword(s):  
Numerical Study ◽  
Precast Concrete ◽  
Concrete Frames ◽  
Moment Resisting

scholarly journals Experimental And Numerical Study To Determine The Relationship Between Tensile Strength And Compressive Strength Of Concrete

2018 ◽  
Vol 4 (11) ◽  
pp. 2787
Author(s):  
Baitollah Badarloo ◽  
Amir Kari ◽  
Faezeh Jafari
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Numerical Study ◽  
Strength Criterion ◽  
Tensile Tests ◽  
Building Codes ◽  
Laboratory Research ◽  
Compressive Strength Of Concrete ◽  
The Relationship

As one of the most widely used materials in different structures, concrete is a material evaluated and categorized based on compressive strength criterion. In addition, national and international codes (INBC- part 9) and standards determine the tensile strength of concrete based on its compressive strength. The purpose of this research is to determine the relationship between compressive strength and tensile strength of C20, C30 and C40 grades. In this laboratory research, a total of 42 cubic specimens of 150 × 150 × 150 mm and 42 cylindrical specimens of 300 × 150 mm were assessed under compressive and tensile tests, respectively. Based on the results of this study, the relationships presented in Ninth Article of Iranian National Building Codes, ACI-318 and Euro Code 2 have been evaluated.

scholarly journals CONSTITUTIVE MATERIAL MODEL FOR BLOCK MASONRY AND ITS MECHANICAL PROPERTIES

2021 ◽  
Vol 16 (4) ◽  
Author(s):  
Muhammad Junaid Iqbal
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Research Work ◽  
Concrete Block ◽  
Material Model ◽  
Unit Weight ◽  
Constitutive Material Model ◽  
Compressive Strength Test ◽  
Average Unit ◽  
Compressive Strength Of Concrete

This research work aims at the development of a material model for concrete block masonry used in the load-bearing wall as well as masonry infill. To accomplish this, various tests were performed on concrete block (solid) units and concrete block masonry assemblage. A concrete block having a size of 12 x 8 x 6 inches, were fabricated in a mortar ratio of 1:4, 1:2:2, 1:8 and 1:4:4. The compressive strength of concrete block prisms having size 24.36 x 8.04 x 18.72 inches, was also determined by conducting the compressive strength test. The shear strength of square prisms, having size 26.76 x 8.04 x 25.20 inches, was found by applying diagonal loading. To investigate the bond shear strength of concrete block masonry, triplet tests were carried out on block masonry prisms. Before conduct, a test on block assemblage specimens, the constituent materials of block assemblage i.e. block and mortar were also tested for different properties. The average compressive strength of concrete block (12”x8”x6”) was 302.25 psi and the average unit weight was 119.83 lb/ft3. The compressive strength of mortars of 1:4, 1:2:2, 1:8 and 1:4:4 was 2367, 1752,815 and 1332 psi respectively.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

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