scholarly journals PERENCANAAN GELAGAR BETON PRATEGANG PADA JEMBATAN PUCOK ALUE, KEC. BAKTIYA KAB. ACEH UTARA

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Khairul Miswar ◽  
Ira Devinta
Keyword(s):  
Post Tension ◽  
Wire Strand

Jembatan Pucok Alue adalah jembatan yang terletak di Kecamatan Baktiya, Kabupaten Aceh Utara. Jembatan ini direncanakan dengan panjang bentang 20 meter dan lebar 6 meter. Gelagar arah memanjang direncanakan untuk jembatan tersebut adalah gelagar tipe beton prategang pascatarik (post-tension). Ruang lingkup perencanaan gelagar  meliputi pendimensian gelagar, pembebanan dengan aturan Standar Pembebanan untuk Jembatan SNI 1725-2016, gaya prategang, eksentrisitas, jumlah tendon, tegangan yang timbul, kehilangan prategang, kapasitas penampang, kontrol lendutan, dan penggambaran. Mutu beton yang digunakan adalah fc = 40 MPa, tendon yang digunakan adalah seven wire strand diameter ½ inch dengan selongsong tendon diameter 60 mm. Tegangan tendon ƒpu 1860 MPa, mutu tulangan baja ulir adalah fy 320 Mpa, dan mutu tulangan baja polos adalah fy 240 MPa. Jumlah tendon yang didapat dari perhitungan adalah 4 buah dengan 10 buah strand dan total sebanyak 40 strand. 

scholarly journals PERENCANAAN JEMBATAN SUNGAI MAPPAJANG DENGAN JEMBATAN BETON PRATEGANG

2019 ◽  
Vol 4 (1) ◽  
pp. 782-787
Author(s):  
Parea Rusan Rangan
Keyword(s):  
Post Tension ◽  
Wire Strand

 Jembatan adalah suatu konstruksi yang berfungsi untuk meneruskan jalan melalui suatu rintangan yang berada lebih rendah. Rintangan ini dapat berupa jalan lain (jalan air atau jalan lalu lintas biasa). Penelitian ini dilakukan untuk merencanakan bangunan atas jembatan sungai Mappajang. Jembatan ini akan menghubungkan Desa Bau ke kecamatan Bonggakaradeng, dengan bentangan jembatan 60 m dan lebar 6 m. Untuk gelagar jembatan direncanakan menggunakan gelagar prategang dengan metode ‘Post Tension”.. Selain itu juga direncanakan bangunan pelengkap seperti pipa sandaran, tiang sandaran, trotoar, penghubung geser dan elastomer. Metode penelitian dilakukan dengan cara mengumpulkan data yang diperlukan untuk perencanaan sungai Mappajang. Data tersebut diantaranya  berupa data primer dan data sekunder. Setelah dilakukan analisis, untuk gelagar prategang  dipakai untaian kawat “Seven Wire Strand” dan digunakan 4 buah tendon pada tiap gelagar. Untuk plat lantai kendaraan komposit dipakai penghubung geser menggunakan angkur 2 D 16 mm. Digunakan elastomer dengan ukuran 500x250 mm yang terdiri dari 3 lapis baja laminasi dengan tebal tiap baja 3 mm.

Effect of Modeling Variables upon Projection of Corrosion-Induced Bridge Post-Tension Tendon Failures

CORROSION ◽  
10.5006/2710 ◽  
2018 ◽  
Vol 74 (7) ◽  
pp. 768-775 ◽  
Author(s):  
William H. Hartt
Keyword(s):  
Tensile Strength ◽  
Concrete Structures ◽  
Random Numbers ◽  
Tendon Length ◽  
The Past ◽  
Modeling Approach ◽  
Bridge Structures ◽  
Post Tensioning ◽  
Post Tension ◽  
Wire Strand

Construction via post-tensioning (PT) has evolved over the past 60 y as an often preferred approach to affecting integrity for large concrete structures. In the case of bridges, tendon ducts typically contain multiple 15.24 mm (0.600 in) diameter, seven wire strands of minimum tensile strength 1,960 kN (270 ksi), and are invariably grouted. However, failures have been reported as a consequence of corrosion caused by either chemically or physically deficient grout. In response to this a methodology was developed and reported whereby the timing of wire and strand fractures and tendon failures can be projected. The present paper reviews basics of the modeling approach and evaluates the influence of modeling variables upon failure projections. These variables include the following: (1) analysis variables (generation of random numbers), (2) strand/tendon stress, (3) wire/strand strength, (4) number of tendons, and (5) tendon length. The significance of each is discussed and results are related to the timing of tendon failures on bridge structures.

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

A new steel anchorage system for post-tensioning applications using carbon fibre reinforced plastic tendons

1998 ◽  
Vol 25 (1) ◽  
pp. 113-127 ◽  
Author(s):  
Ezzeldin Y Sayed-Ahmed ◽  
Nigel G Shrive
Keyword(s):  
Carbon Fibre ◽  
Prestressed Concrete ◽  
Fatigue Tests ◽  
Direct Tension ◽  
Element Analysis ◽  
Prestressing Steel ◽  
Reinforced Plastics ◽  
Anchorage System ◽  
Post Tensioning ◽  
Post Tension

During the past half century, the use of prestressing in different structures has increased tremendously. One of the most important techniques of prestressing is post-tensioning. The main problem associated with post-tensioning in different structures is the corrosion of the prestressing steel tendons even with well-protected steel. New materials, fibre reinforced plastics or polymers (FRP), which are more durable than steel, can be used for these tendons/strands and thus overcome the corrosion problem. However, different shortcomings appear when FRP tendons are introduced to post-tensioning prestressing applications. For carbon fibre plastic tendons (CFRP), there is no suitable anchorage system for post-tensioning applications. Some of the anchorages developed by others for use with FRPs are therefore described and assessed. A new anchorage system developed by the authors, which can be used with bonded or unbonded CFRP tendons in post-tensioning applications, is described. The results of direct tension and fatigue tests on CFRPs anchored with the new system are presented.Key words: anchorage system, cyclic loading, fatigue, fibre reinforced plastics, finite element analysis, post-tension, prestressed concrete, prestressed masonry, strands, tendons.

scholarly journals Anchorage and residual bond characteristics of 7-wire strand

2017 ◽  
Vol 138 ◽  
pp. 1-16 ◽  
Author(s):  
J.J. Orr ◽  
Antony Darby ◽  
Tim Ibell ◽  
Nick Thoday ◽  
Pierfrancesco Valerio
Keyword(s):  
Wire Strand ◽  
Bond Characteristics

Fungal Influenced Corrosion in Post-Tension Structures

2001 ◽  
Vol 10 (4) ◽  
pp. 44-48
Author(s):  
Brenda Little ◽  
Roger W. Staehle
Keyword(s):  
Tension Structures ◽  
Post Tension
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