scholarly journals Experimental Behavior of the Curved Continuous Twin I-Girder Composite Bridge with a Precast Concrete Slab Subjected to Bending, Shear, and Torsion

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Chuandong Shen ◽  
Yifan Song ◽  
Lei Yan ◽  
Yuan Li ◽  
Xueli Wang ◽  
...  
Keyword(s):  
Failure Mode ◽  
Concrete Slab ◽  
Load Capacity ◽  
Precast Concrete ◽  
Plastic Hinge ◽  
Local Buckling ◽  
Design Load ◽  
Symmetric Point ◽  
Bridge Model ◽  
Composite Bridge

In order to investigate the mechanical behavior, ultimate load carrying capacity, and failure mode of the intact curved continuous twin I-girder composite bridge (TGCB) with a precast concrete slab, one curved continuous composite bridge model with a scale ratio of 1 : 5 of a prototype bridge was designed and manufactured considering the influence of the construction sequence. Four symmetric point loads’ test was carried out. In this paper, load-deflection relationship and strain development of steel girders, concrete slab, and reinforcement at key sections were tested and analyzed. Failure mode, crack development, and major crack width at the top surface of the concrete slab in the hogging moment region were also reported. The experimental results demonstrated that the load capacity under the initial cracking level, cracking level with the width of 0.2 mm, and steel girder yielding state is about 1.7, 5.0, and 6.3 times of the design load, respectively. Due to the influence of curvature, the stiffness of the external girder is less than that of the internal girder. However, the ultimate bearing capacity is basically the same, approximately 13.6 times of the design load. During the loading process, plastic hinge was first observed at the intermediate support section as a result of the hogging moment which should be emphasized in design. The local buckling took place after yielding, indicating a class 2 section according to Eurocode 4. In addition, the TGCB had good ductility since the displacement ductility coefficients of the external and internal girders were 4.40 and 4.06, respectively.

scholarly journals Ultimate Limit Design of Strengthened Steel Columns by Mortar-Filled FRP Tubes

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jian Hou ◽  
Li Song
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Load Capacity ◽  
Composite Columns ◽  
Steel Columns ◽  
Frp Tube ◽  
Frp Tubes ◽  
Ultimate Limit

The present study investigated the various failure modes of strengthened steel columns by mortar-filled fiber-reinforced polymer (FRP) tubes to analytically formulate the ultimate capacities of these steel columns. A simple and effective method, wherein a mortar-filled FRP tube was sleeved outside the steel member, was also formulated to enhance the buckling resistance capacity of compressed steel members. In addition, to facilitate the connection of the column to other structural members, the length of the sleeved mortar-filled FRP tubes is less than that of the original steel columns. Theoretical analyses were also performed on the critical sections of such composite columns at their ultimate states to identify their potential failure modes, such as FRP-tube splitting at the ends or on the insides of wrapped areas, local buckling at the steel ends of transition zones, and global buckling of the composite columns. The corresponding ultimate capacity of each failure mode was then analytically formulated to characterize the critical failure mode and ultimate load capacity of the columns. The current theoretical results were compared with those from literature to validate the applicability of the developed ultimate limit design approaches for FRP-mortar-steel composite columns.

Flexural Behaviour of Reinforced Slab Panel System with Embedded Cold-formed Steel Frames as Reinforcement

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Cher Siang Tan ◽  
Yee Ling Lee ◽  
Shahrin Mohammad ◽  
Siong Kang Lim ◽  
Yeong Huei Lee ◽  
...  
Keyword(s):  
Concrete Slab ◽  
Load Capacity ◽  
Precast Concrete ◽  
Steel Frames ◽  
Control Sample ◽  
Steel Frame ◽  
Ultimate Load Capacity ◽  
Hollow Section ◽  
Average Value ◽  
Cold Formed Steel

This paper presents the experimental investigation on flexural characteristic of slab panels with embedded cold-formed steel frame as reinforcement. Perforated cold-formed steel channel sections are formed into steel frames as replacement to the conventional reinforcement bars inside precast concrete slab panels. A series of six experimental specimens for precast slab panels were tested. The specimens with 3 configurations namely control sample (CS) with conventional reinforcement bars, single horizontal C-channel section (SH) and double horizontal C-channel sections (DH) formed into rectangular hollow section. Results show that the tested slab specimens failed at the flexural crack at mid-span, under loading point and shear at the support. Tearing of shear connector in the cold-formed steel section was found to be the main factor for the structural failure. SH specimens achieved the highest ultimate load capacity, with average value of 138.5 kN, followed by DH specimens, 116.5 kN, and the control samples, 59.0 kN. The results showed that the proposed reinforced slab panel with embedded cold-formed steel frame was more effective compared to conventional reinforced slab.

Rehabilitation of Tappan Zee Bridge Using Precast Concrete Composite Deck Units

2000 ◽  
Vol 1696 (1) ◽  
pp. 63-72
Author(s):  
Richard N. White ◽  
Peter Smith
Keyword(s):  
Bridge Deck ◽  
Lightweight Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Precast Concrete ◽  
Fatigue Loading ◽  
Hudson River ◽  
Load Level ◽  
Experimental Program ◽  
Specific Reference

The criteria used for successful rehabilitation of decks of major bridges when it is not feasible to close the bridge to traffic are described. These criteria are described with specific reference to recent work on the trestle spans of the Tappan Zee Bridge over the Hudson River near New York City. The results of an experimental program conducted with a full-scale, 10-m-span, lightweight concrete slab-steel beam composite bridge deck unit intended for later use in rehabilitating the through-truss decks of the bridge are also described. Loading history included 107 cycles of flexural fatigue loading followed by a flexural load capacity test. Measured values of capacity and midspan deflection at this ultimate load level are compared with simplified analytical predictions. A description of the actual rehabilitation process used on the Tappan Zee Bridge deck is also provided.

The Influence of Slab Concreting Sequence on a Continuous Composite Girder Bridge

2016 ◽  
Vol 691 ◽  
pp. 96-107
Author(s):  
Tomas J. Zivner ◽  
Rudolf B. Aroch ◽  
Michal M. Fabry
Keyword(s):  
Concrete Slab ◽  
Transverse Cross Section ◽  
Slab Thickness ◽  
Slab Width ◽  
Composite Girder ◽  
Steel Members ◽  
Composite Bridge ◽  
Bridge Girder ◽  
Girder Bridge ◽  
Main Girder

This paper deals with the slab concreting sequence and its influence on a composite steel and concrete continuous highway girder bridge. The bridge has a symmetrical composite two-girder structure with three spans of 60 m, 80 m, 60 m (i.e. a total length between abutments of 200.0 m). The horizontal alignment is straight. The top face of the deck is flat. The bridge is straight. The transverse cross-section of the slab is symmetrical with respect to the axis of the bridge. The total slab width is 12 m. The slab thickness varies from 0.4 m on main girders to 0.25 m at its free edges and 0.3075 m at its axis of symmetry. The center-to-center spacing between main girders is 7 m and the slab cantilever on either side is 2.5 m long. Every main girder has a constant depth of 2800 mm and the thicknesses of the upper and lower flanges are variable. The lower flange is 1200 mm wide whereas the upper flange is 1000 mm wide. The two main girders have transverse bracing at abutments and at internal supports and at regular intervals in every span. The material of concrete slab is C35/45 and of steel members S355. The on-site pouring of the concrete slab segments is performed by casting them in a selected order and is done after the launching of the steel two girder bridge. The paper presents several concreting sequences and their influence on the normal stresses and deflections of the composite bridge girder.

scholarly journals Finite element analysis of reinforced concrete deep beam with large opening

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elsayed Ismail ◽  
Mohamed S. Issa ◽  
Khaled Elbadry
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
The Other ◽  
Deep Beam ◽  
Web Openings ◽  
Design Load ◽  
Large Opening

Abstract Background A series of nonlinear finite element (FE) analyses was performed to evaluate the different design approaches available in the literature for design of reinforced concrete deep beam with large opening. Three finite element models were developed and analyzed using the computer software ATENA. The three FE models of the deep beams were made for details based on three different design approaches: (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978), (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006), and Strut and Tie method (STM) as per ACI 318-14 (ACI318 Committee, Building Code Requirements for Structural Concrete (ACI318-14), 2014). Results from the FE analyses were compared with the three approaches to evaluate the effect of different reinforcement details on the structural behavior of transfer deep beam with large opening. Results The service load deflection is the same for the three models. The stiffnesses of the designs of (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and STM reduce at a load higher than the ultimate design load while the (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) reduces stiffness at a load close to the ultimate design load. The deep beam designed according to (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) model starts cracking at load higher than the beam designed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) method. The deep beam detailed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) and (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) failed due to extensive shear cracks. The specimen detailed according to STM restores its capacity after initial failure. The three models satisfy the deflection limit. Conclusion It is found that the three design approaches give sufficient ultimate load capacity. The amount of reinforcement given by both (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) is the same. The reinforcement used by the STM method is higher than the other two methods. Additional reinforcement is needed to limit the crack widths. (Mansur, M. A., Design of reinforced concrete beams with web openings, (2006)) method gives lesser steel reinforcement requirement and higher failure load compared to the other two methods.

scholarly journals Bending Behaviour of Dowelled Mortise and Tenon Joints in Kempas

2008 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Rohana Hassan ◽  
Azmi Ibrahim ◽  
Zakiah Ahmad
Keyword(s):  
Load Capacity ◽  
Plastic Hinge ◽  
Shear Plane ◽  
Strength Properties ◽  
Visual Observation ◽  
Tropical Timber ◽  
Wood Dowel ◽  
Bending Load ◽  
Timber Connections ◽  
Mortise And Tenon

Mortise and tenon are commonly used as timber connections between beam and column with enhancement by pultruded dowel. At present the data on the performance of mortise and tenon joints manufactured using Malaysian tropical timber is not available. Therefore there is a need to provide such data for better guidance and references in design purposes. This study investigates the behavior and strength properties of dowelled mortise and tenon timber connections using selected Malaysian tropical timber with different types of dowels namely steel and timber. Bending tests were performed on mortise and tenon beam-column joints of Kempas when plugged with steel or wood dowel. It is found that pegging the connections with the respective steel and timber dowels resulted in a bending load capacity of 6.09 and 5.32 kN, taken as the average of three samples, the latter being 12 % lower than former. Visual observation of the failed test pieces revealed steel dowels exhibiting yield mode Im and wood, mode IIIs. The wood dowels yielded in bending at one plastic hinge point per shear plane with an associated wood crushing while the steel dowels remained practically undeformed with an associated crushing of the main member.

scholarly journals Limitations of the Danish driving formula for short piles

2021 ◽  
Vol 44 (2) ◽  
pp. 1-6
Author(s):  
Silvio Heleno de Abreu Vieira ◽  
Francisco R. Lopes
Keyword(s):  
Load Capacity ◽  
Precast Concrete ◽  
Free Fall ◽  
Technical Note ◽  
Driven Piles ◽  
Concrete Piles ◽  
Load Tests ◽  
Semi Empirical ◽  
The City ◽  
Pile Length

Dynamic formulae are a widely used expedient for the control of driven piles to ensure load capacity. These formulae have considerable limitations when used in the prediction of the load capacity on their own, but are very useful in the control of a piling when combined with other tests. This technical note presents an evaluation of the Danish Formula for 54 precast concrete piles, comparing its results with High Strain Dynamic Tests (HSDTs), Static Load Tests (SLTs) and predictions by a semi-empirical static method (Aoki & Velloso, 1975). The data used in the comparison come from three works in the city of Rio de Janeiro, Brazil. All piles were driven with free-fall hammers and in one particular work the piles were relatively short. The predictions of the Danish Formula were evaluated in relation to the pile length/diameter ratio. It was concluded that for short piles - with lengths less than 30 times the diameter - this formula indicates bearing capacities higher than the actual ones. A correction for a safe use of the Danish Formula for short piles is suggested.

scholarly journals IDENTIFIKASI FAKTOR PENGARUH DOMINAN KETERLAMBATAN PROYEK AKIBAT RANTAI PASOK PADA PENGADAAN PELAT BETON PRACETAK

2020 ◽  
Vol 3 (4) ◽  
pp. 1295
Author(s):  
Firena Bian Saputri ◽  
Basuki Anondho
Keyword(s):  
Supply Chain ◽  
Human Error ◽  
Concrete Slab ◽  
Precast Concrete ◽  
Influence Factors ◽  
Concrete Slabs ◽  
Literature Study ◽  
Factors Affecting ◽  
Project Duration ◽  
Speed Up

One way that can be done to speed up the duration of the project is to use precast concrete slabs. However, the use of precast concrete slab elements in the project can be ineffective if in the order stage, production stage, until the delivery stage of precast concrete elements to the project site is not managed properly, which can cause delays in project duration. Therefore, the use of precast concrete slabs is very dependent on the supply chain management. To anticipate this risk, it is necessary to identify what are the dominant factors in the supply chain that affect the procurement of precast concrete slabs which can cause delays in project duration. The initial influence factors were collected through a literature study and interviews with a number of practitioners, followed by a survey using a questionnaire to a number of project actors in projects using precast concrete slabs. The Likert scale 1-5 is used to measure the level of influence of a factor identified on project delays. By using factor analysis techniques, as many as three groups of dominant supply chain factors affecting the procurement of precast concrete slabs were found, namely special factors, technical factors, and human error factors.ABSTRAKSalah satu cara yang dapat dilakukan demi mempercepat durasi proyek adalah menggunakan pelat beton pracetak. Namun, penggunaan elemen pelat beton pracetak di proyek bisa tidak efektif apabila dalam tahap pemesanan, tahap produksi, hingga tahap pengiriman elemen beton pracetak ke lokasi proyek tidak dikelola dengan baik, sehingga dapat menyebabkan keterlambatan durasi proyek. Oleh sebab itu, penggunaan pelat beton pracetak sangat bergantung pada manajemen rantai pasokannya. Untuk mengantisipasi risiko tersebut, perlu adanya identifikasi mengenai faktor dominan apa saja pada rantai pasok yang mempengaruhi pengadaan pelat beton pracetak yang dapat menyebabkan keterlambatan durasi proyek. Faktor pengaruh awal dikumpulkan melalui studi literatur dan wawancara kepada sejumlah praktisi, dilanjutkan dengan survei menggunakan kuesioner kepada sejumlah pelaku proyek di proyek yang menggunakan pelat beton pracetak. Skala Likert 1-5 digunakan untuk mengukur tingkat pengaruh suatu faktor yang diidentifikasi terhadap keterlambatan proyek. Dengan menggunakan teknik analisis faktor, sebanyak tiga kelompok faktor dominan rantai pasok yang berpengaruh pada proses pengadaan pelat beton pracetak ditemukan, yaitu faktor khusus, faktor teknis, dan faktor human error.

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