Experimental–theoretical investigation of the short-term vibration response of uncracked prestressed concrete members under long-age conditions

Structures ◽  
2022 ◽  
Vol 35 ◽  
pp. 260-273
Author(s):  
Marco Bonopera ◽  
Wen-Cheng Liao ◽  
Wisena Perceka
2003 ◽  
Vol 9 (4) ◽  
pp. 280-283 ◽  
Author(s):  
Renata Zamblauskaitė ◽  
Gintaris Kaklauskas ◽  
Darius Bačinskas ◽  
Morten Bo Christiansen

In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short-term deformational analysis of flexural prestressed concrete members. The relationship of tensile concrete is based on smeared crack approach and accumulates cracking and the tension stiffening effects. The Flexural constitutive model was applied in a simple engineering technique based on principles of strength of materials and the layered approach. To assess accuracy of the technique, deflections have been calculated for experimental prestressed concrete beams reported in the literature. Comparison has been earned out with the predictions of the well-known design code methods of different countries.


PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.


2005 ◽  
Vol 32 (3) ◽  
pp. 463-479 ◽  
Author(s):  
Marc-André Bérubé ◽  
Nizar Smaoui ◽  
Benoit Fournier ◽  
Benoit Bissonnette ◽  
Benoit Durand

The expansion attained by a concrete affected by alkali-silica reaction (ASR) is an important parameter in the evaluation of the corresponding structure. In part I, relationships were established in the laboratory between the ASR expansion and the stiffness damage test (SDT), the damage rating index (DRI), and the cumulated width of cracks observed at the surface of concrete specimens made with various types of reactive aggregates. In part II, these relationships were verified in the case of specimens made in laboratory but exposed outdoors. In part III, the aforementioned methods were applied to three ASR-affected structures. The measurement of crack widths at the surface of the affected members allowed a rather good estimation of the concrete expansion, provided the measurements were taken on the most severely exposed sections of these members. The DRI did not allow differentiating the most visually and mechanically affected concretes from the least affected concretes. The SDT proved to be the most interesting method to date for evaluating the expansion of ASR-affected concrete; however, it seemed to underestimate the expansion of the prestressed concrete members investigated.Key words: aggregates, alkali–silica reaction, concrete, petrography, expansion, stiffness, cracking.


1996 ◽  
Vol 122 (3) ◽  
pp. 291-297 ◽  
Author(s):  
B. M. Luccioni ◽  
J. C. Reimundín ◽  
R. Danesi

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