Formula of Unbonded Tendon Stress Increment Based Performance

2014 ◽  
Vol 501-504 ◽  
pp. 815-818
Author(s):  
Jian Qiang Han ◽  
Yuan Yuan Yu ◽  
Xiu Yan Fu
Keyword(s):  
Prestressed Concrete ◽  
Concrete Structure ◽  
Precast Concrete ◽  
Scientific Basis ◽  
Frame Structure ◽  
Stress Increment ◽  
Stress Calculation ◽  
Unbonded Tendons ◽  
Tendon Strain ◽  
External Loads

Unbonded tendon stress calculation of unbonded precast concrete structure is defferent from prestressed concrete structure, as tendon strain caused by the external load is not in accordance with relevant sections of the concrete strain obtained. As the deformation of unbonded tendons are not subject to the deformation of plane-section assumption, therefore, arise due to external loads of unbonded tendon stress calculation is more complex. In this paper, based on theoretical analysis and derivation, the pre-stress deformation of the unbonded steel stress formula was given, this can provide more scientific basis for the stress Analysis of unbonded precast frame structure.

scholarly journals Experimental Study of a New Precast Prestressed Concrete Joint

2018 ◽  
Vol 8 (10) ◽  
pp. 1871 ◽  
Author(s):  
Xueyuan Yan ◽  
Suguo Wang ◽  
Canling Huang ◽  
Ai Qi ◽  
Chao Hong
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Frame Structure ◽  
Loading Test ◽  
Concrete Frame ◽  
Concrete Joints ◽  
Precast Prestressed Concrete

Precast monolithic structures are increasingly applied in construction. Such a structure has a performance somewhere between that of a pure precast structure and that of a cast-in-place structure. A precast concrete frame structure is one of the most common prefabricated structural systems. The post-pouring joint is important for controlling the seismic performance of the entire precast monolithic frame structure. This paper investigated the joints of a precast prestressed concrete frame structure. A reversed cyclic loading test was carried out on two precast prestressed concrete beam–column joints that were fabricated with two different concrete strengths in the keyway area. This testing was also performed on a cast-in-place reinforced concrete joint for comparison. The phenomena such as joint crack development, yielding, and ultimate damage were observed, and the seismic performance of the proposed precast prestressed concrete joint was determined. The results showed that the precast prestressed concrete joint and the cast-in-place joint had a similar failure mode. The stiffness, bearing capacity, ductility, and energy dissipation were comparable. The hysteresis curves were full and showed that the joints had good energy dissipation. The presence of prestressing tendons limited the development of cracks in the precast beams. The concrete strength of the keyway area had little effect on the seismic performance of the precast prestressed concrete joints. The precast prestressed concrete joints had a seismic performance that was comparable to the equivalent monolithic system.

scholarly journals Comparative Studies between Precast and Conventional Cast-In-Situ Structural Systems

2021 ◽  
Vol 1197 (1) ◽  
pp. 012062
Author(s):  
Aman Agrawal ◽  
S.S. Sanghai ◽  
Kuldeep Dabhekar
Keyword(s):  
Comparative Studies ◽  
Concrete Structure ◽  
High Speed ◽  
Precast Concrete ◽  
Mode Shapes ◽  
Structural Systems ◽  
Seismic Loads ◽  
Time Frames ◽  
External Loads

Abstract In India, greatest constructional exercises are finished utilizing the old convectional cast in situ strategies since seemingly forever. As the nation is creating in a high speed, the necessity for lodging is heightening and in this way the development ventures are additionally blossoming quickly henceforth requesting quicker and better development techniques. This expanded interest can be coordinated by utilizing one of the cutting-edge innovations, pre-projected substantial strategy. Investigation of writing shows various priority of precast constructional strategy over different techniques for development. Appropriately, this investigation presents the examination and plan of g+5 floor precast concrete structure and traditional cast-in-situ structure. The designs were demonstrated and investigated utilizing Etabs programming for dead, forced, and seismic loads and for load combinations. The fundamental intention was to consider the conduct of both the sorts of structures under the previously mentioned loads and load mixes. Examination was directed dependent on different components like external loads, greatest deflections, most extreme story drifts, mode shapes, time-frames, frequencies and base shears.

Increase of stress in unbonded tendons in prestressed concrete beams and slabs

1981 ◽  
Vol 8 (2) ◽  
pp. 262-268 ◽  
Author(s):  
Perumalsamy N. Balaguru
Keyword(s):  
Prestressed Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Regression Equation ◽  
Prestressing Force ◽  
Unbonded Tendons ◽  
Stress Strain Relation ◽  
Stress Changes ◽  
Tendon Strain ◽  
Suggested Formula

In the case of prestressed concrete beams with unbonded tendons, in order to design for strength and serviceability, one has to evaluate the effective prestressing force in the tendon, which is beam dependent rather than section dependent, both at ultimate and working loads. The formulae available in the published literature deal only with ultimate load conditions. A simple equation to predict the tendon stress changes for the complete loading range is presented in this paper. The formula was developed using the basic theory of flexure to obtain the equation for the elastic curve, and numerical integration to obtain the curve lengths. Using the computer generated results of the increase in tendon strain for various span lengths, eccentricities, and maximum deflections, a regression equation was developed. This regression equation predicts the increase in tendon strains as a function of the span–eccentricity and eccentricity – maximum deflection ratios. The recently published stress–strain relation which seems to be very accurate is then used to predict the tendon stress. The results are compared with a set of experimental results. The suggested formula is also consistent with some of the available equations for the prediction of the tendon stress at ultimate load.

Experimental Study on the Stress Increment of Prestressed Tendons of Retard-Bonded Prestressed Concrete Continuous Beams

2010 ◽  
Vol 163-167 ◽  
pp. 1431-1435 ◽  
Author(s):  
Qiang Fu ◽  
Xia Cao ◽  
Ling Zhi Jin ◽  
Wan Xu Zhu ◽  
Hui Xian Yang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Prestressed Concrete ◽  
Technical Specification ◽  
Continuous Beam ◽  
Stress Increment ◽  
Concrete Members ◽  
Continuous Beams ◽  
Unbonded Tendons ◽  
Working Performance ◽  
Made In

Based on the bending experiment for two-span continuous beams of retard-bonded prestress concrete, the analysis of the stress increment of prestressed tendons is made in the loading process. The theory that the working performance of retard-bonded prestressed concrete members is as same as unbonded prestressed concrete members during the retarding period is demonstrated. It is feasible to use the formulas for the reference (Technical specification for concrete structures prestressed with unbonded tendons) to calculate σputhe ultimate stress and Δσp the Stress increment of the retard-bonded prestressed tendons and the recommended formulas are advised to use. It is also demonstrated that retard-bonded prestressed concrete members have the same working performance as bonded prestressed concrete members after the retarding period. The conclusion of this paper can provide the reference date for the design of retard-bonded prestressed concrete continuous beam.

Precast Prestressed Concrete Structure Provides Solution for Getty Center Tram Guideway

PCI Journal ◽  
1995 ◽  
Vol 40 (3) ◽  
pp. 24-39 ◽  
Author(s):  
Mark G. Josten ◽  
Wilfred L. Painter ◽  
James S. Guarre
Keyword(s):  
Prestressed Concrete ◽  
Concrete Structure ◽  
Precast Prestressed Concrete

Tolerances for Precast Concrete Structure

PCI Journal ◽  
1976 ◽  
Vol 21 (4) ◽  
pp. 44-57
Author(s):  
Marvin L. Vander ◽  
H. Carl Walker
Keyword(s):  
Concrete Structure ◽  
Precast Concrete

Robust Stress Check Formula of Lifting Padeye

2010 ◽  
Vol 54 (01) ◽  
pp. 34-40
Author(s):  
Zhou Bo ◽  
Liu Yujun ◽  
Ji Zhuoshang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Accurate Method ◽  
Offshore Structures ◽  
Structure Design ◽  
Stress Calculation ◽  
Check Method ◽  
External Loads ◽  
Actual Stress ◽  
Element Method

Lifting padeyes are widely used in the construction of offshore structures and ships. It has been shown that the traditional check method cannot reflect the realistic value and distribution of actual stress on the padeyes. A more accurate method for the padeye stress calculation is essential and important for promoting the safety of the padeyes. In this paper, a new check formula is proposed based on the analysis of deformation and external loads distribution on lifting padeyes. The results of finite element method and the solutions of traditional check formula and new check formula are compared. It is shown that, by applying the stress check formula derived in the paper, the value and the location of the dangerous stresses occurred can be evaluated easily and exactly. The safe reliability of structure design can be improved significantly.

Experimental investigation of seismic performance of a novel isostatic frame-cladding system

2022 ◽  
pp. 136943322110572
Author(s):  
Xun Chong ◽  
Pu Huo ◽  
Linlin Xie ◽  
Qing Jiang ◽  
Linbing Hou ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Damage Evolution ◽  
Failure Modes ◽  
Static Load ◽  
Precast Concrete ◽  
Frame Structure ◽  
Deformation Capacity ◽  
Load Bearing Capacity ◽  
Cladding Panels ◽  
Energy Dissipation Capacity

A new connection measure between the precast concrete (PC) cladding panel and PC frame structure is proposed to realize a new kind of isostatic frame-cladding system. Three full-scale PC wall-frame substructures were tested under the quasi-static load. These substructures included a bare wall-frame specimen, a specimen with a cladding panel that has no opening, and a specimen with a cladding panel that has an opening in it. The damage evolution, failure mode, load-bearing capacity, deformation capacity, and energy dissipation capacity of three specimens were compared. The results indicated that the motions of the cladding panels and the main structures were uncoupled through the relative clearance of the bottom connections, and three specimens exhibited approximately identical failure modes and seismic performance. Thus, the reliability of this new isostatic system was validated.

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