scholarly journals Numerical Investigation of Innovative Support Frame of Openings in the Segmental Tunnel Lining

2020 ◽  
Vol 14 (1) ◽  
pp. 358-369
Author(s):  
Sanaz Ebrahimi ◽  
Mir Raouf Hadei ◽  
Alireza Rashiddel ◽  
Mohsen Hajihassani
Keyword(s):  
Support System ◽  
Steel Structures ◽  
Steel Frame ◽  
Concrete Lining ◽  
Reinforced Concrete Frame ◽  
Maximum Displacement ◽  
Segmental Lining ◽  
Concrete Frame ◽  
Temporary Support ◽  
Stress And Deformation

Introduction: To supply safety in the tunnels, it is necessary to construct escape routes and emergency exits that are performed by locating cross passages. Methods: These passages connect two tunnels transversely and apply escape routes. Using temporary steel structures to supply the ring stability in practice and reinforced concrete frame to stabilize the ring permanently can be appropriate to form a solid frame that transfers the opened ring's load to the opening surroundings. In this paper, a 3D finite element simulation was performed to analyze the influence of opening construction in the segmental concrete lining and a temporary support system. Using the simulation, stress and deformation distribution of the steel frame, bolts, and segmental lining were obtained. Results: The results show that by increasing the number of bolts from 18 to 30, the induced stress in the steel frame and bolts decreased to 76 and 59 percent, respectively. In addition, the maximum displacement in the segmental lining and the maximum opening value of the joints decline to 62.7 and 75 percent, respectively. Conclusion: Finally, it can be concluded that the steel frame can be used as a temporary support system.

scholarly journals Deformation of Overlong Isolated Buildings Caused by Thermal and Concrete Shrinkage

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Dang ◽  
Ying-ke Liu
Keyword(s):  
Thermal Strain ◽  
Thermal Action ◽  
Thermal Design ◽  
Reinforced Concrete Frame ◽  
Distribution Method ◽  
Temperature Variations ◽  
Concrete Frame ◽  
Concrete Shrinkage ◽  
Theoretical Predictions ◽  
Stress And Deformation

Temperature variations and concrete shrinkage influence structural behavior by reducing the strength of materials and changing their thermal strain contributions. This problem is particularly important for isolated buildings that are characterized by large horizontal dimensions and are sensitive to thermal action and shrinkage. In this study, the measurement of an overlong isolated building shows that the deformations of some isolators exceed the allowed deviation during the construction phase because the building is completely exposed. These deformations are induced by climatic thermal changes and shrinkage effects and cause the complex dynamic behavior and instability of the structure. To ensure the safety of overlong isolated buildings, the structural stress and deformation caused by temperature variations and shrinkage effects are studied. A three-story frame model is developed, and the rule of deformation within isolated frame buildings is analyzed by the deformation distribution method. The theoretical predictions are consistent with the experimental measurements. Therefore, the theoretical model is used to predict the deformation of isolated buildings caused by temperature variations and shrinkage effects. For reinforced concrete frame isolated buildings, expansion joint distances are proposed according to different thermal design regions and heating design conditions.

Comparison on Dynamic Parameters of Structures with Different Additional Steel Frame Stories Constructed on the Prototype Reinforced Concrete Frame

2013 ◽  
Vol 438-439 ◽  
pp. 756-761
Author(s):  
Jian Xue Song ◽  
Hong Tuan Wu ◽  
He Shan Cheng
Keyword(s):  
Reinforced Concrete ◽  
Shear Force ◽  
Horizontal Displacement ◽  
Steel Frame ◽  
Original Structure ◽  
Dynamic Parameters ◽  
Reinforced Concrete Frame ◽  
Vibration Period ◽  
Concrete Frame ◽  
Displacement Angle

Based on a practical project, the dynamic parameters for a 4-story reinforced concrete frame, with additional different stories of steel frame constructed on its top, are investigated, including vibration period, frequency, and seismic response under minor shock, such as inter-story maximum horizontal displacement, inter-story maximum horizontal displacement angle, inter-story shear force and so on. It reveals that the maximum number of additional stories may be determined by the inter-story maximum horizontal displacement angle. With the additional steal frame adding on the top of the original structure, the maximum horizontal displacement angle often comes into being as the second story from the top of the structure, at the same time, a certain story in the prototype structure may evolve into a weak story which has to be reinforced. However, with the increasing of additional stories, the total shear force in the bottom story decreases, which leads to a new anti-seismic design concept.

Mechanical Simulation of Reinforced Concrete Frame Structure

2012 ◽  
Vol 256-259 ◽  
pp. 689-692
Author(s):  
Hui Na Jia ◽  
Gao Wei Yue
Keyword(s):  
Reinforced Concrete ◽  
Constant Load ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Element Analysis ◽  
Concrete Frame ◽  
The Finite Element Analysis ◽  
Reinforced Concrete Frame Structure ◽  
Calculation Results ◽  
Stress And Deformation

In this paper the theoretical model of reinforced concrete frame structure is established to numerically simulate and analyze its overall morphology with the finite element analysis method. The calculation results shows that at the bottom of the structure the stress and deformation is much larger than other parts with the action of constant load, live load and wind load. And with modal analysis and buckling analysis natural frequency and vibration mode are obtained to avoid resonance and predict the buckling load.

scholarly journals Precast Bridges of Bamboo Reinforced Concrete in Disadvantaged Village Areas in Indonesia

2020 ◽  
Vol 10 (20) ◽  
pp. 7158
Author(s):  
Muhtar
Keyword(s):  
Reinforced Concrete ◽  
Precast Concrete ◽  
High Water ◽  
Concrete Bridge ◽  
Reinforced Concrete Frame ◽  
Maximum Displacement ◽  
Maximum Deformation ◽  
Concrete Frame ◽  
Bridge Plate ◽  
Bridge Technology

Bamboo is an inexpensive, environmentally friendly, and renewable building material that thrives in Indonesia. Bamboo has a high tensile strength but also has weaknesses, namely, it is easily attacked by insects and has high water absorption. Utilization of bamboo as a precast concrete bridge reinforcement must be treated first through soaking, drying, and giving a waterproof coating and sand. This research aimed to obtain a precast bamboo reinforced concrete bridge technology with good integrity, with measuring parameters of deformation and deflection according to AASHTO standards. The dimensions of the bridge were a span of 320 cm, a width of 224 cm, and a height of 115 cm. Two bridge frames were connected by four bridge beams. The bridge plate was made of a 10-cm-thick concrete plate. The bridge support of the reinforced concrete is assumed to be the hinge support and the rubber bearing is assumed to be the roller support. The bamboo reinforced concrete frame bridge test was carried out directly with a load of a minibus-type vehicle. The test results show that the precast bamboo reinforced concrete frame bridges have sufficiently good integrity; that is, they can distribute loads with deflection and deformation that do not exceed their permits. The maximum displacement occurs in the bridge frame of 0.25 mm, meeting the requirements based on the AASTHO and RSNI T-12-2004 standards, which is not more than Δmax = L/800 = 3.75 mm. The maximum deformation occurs in the bridge beam of 0.20 mm, and the bridge frame of 0.13 mm meets the requirements based on the AASTHO and RSNI T-12-2004 standards, which is not more than δmax = L/800 = 3.75 mm.

scholarly journals Analisis Kinerja Struktur Rangka Beton Bertulang Beraturan Dengan Penambahan Tingkat Menggunakan Struktur Baja

2021 ◽  
Vol 1 (2) ◽  
pp. 36-47
Author(s):  
Hilario Alberto Kono ◽  
Partogi H Simatupang ◽  
Ruslan Ramang
Keyword(s):  
Structural Model ◽  
Steel Structures ◽  
Frame Structure ◽  
Building Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Drift Ratio ◽  
Reinforced Concrete Frame Structure ◽  
Interstorey Drift ◽  
Immediate Occupancy

The change of plans on gradually development in building structure can be occur with building operational consideration and owner financial. The purpose of this study was to determine the level of performance of the reinforced concrete frame structure with additional levels using steel structures with different span variations. The results of the analysis are used to determine how big the deviation is between levels and to control the level of structure performance. The conclusion of the study shows that the performance level of the structural model analyzed is immediate occupancy (IO) with a total drift ratio and interstorey drift ratio value of the initial building structure (C3S0) in the x direction and y direction of 0.0004, and for variations in building structure with the addition of levels using steel structures (C3S1, C3S2, C5S1, C5S2, C7S1, C7S2) in the x direction ranging from 0.0005-0.0007 and in the y direction ranging from 0.0010-0.0024.

scholarly journals An Investigation on Sheeting Acting as a Diaphragm on a Reinforced Precast Concrete Frame

2020 ◽  
Author(s):  
Sergiu-Gheorghe Țere ◽  
Bogdan Hegheș ◽  
Horea Constantinescu
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Precast Concrete ◽  
Steel Structures ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Concrete Frame ◽  
Steel Sheets ◽  
Starting Point

It is well-known that for single-storey steel structures, the framework is greatly strengthened and stiffened following the attachment of the roof, floors and walls. The panels in the roofing, flooring and side cladding are also known as “shear diaphragms” by virtue of their resistance to being deformed into parallelograms. This has been verified by on-site practical experience of many structures and design provisions are available for structural engineers. Despite the fact that for single-storey structures, the corrugated steel sheets are the standard elements in constructing the envelopes, in what concerns the reinforced concrete frames there are no guidelines nor recommendations on how to consider the diaphragm effect in structural analysis. In order to better understand the interaction between the corrugated steel sheets and the reinforced concrete frame, a real precast reinforced concrete frame structure was built for experimental testing. The aim of the experimental test is to study the diaphragm effect for reinforced concrete structures and based on the results to identify the discrepancies identified compared to steel structures. The investigation attempts to provide a starting point for future research on the stressed skin design acting on reinforced concrete frames. At the end of the article conclusions are drawn based on the experience obtained during the experimental test.

Time-Varying Law Experimental Research of the Interaction of Concrete Structure and Formwork Support during the Construction Period

2014 ◽  
Vol 488-489 ◽  
pp. 466-469
Author(s):  
Qing Rong Tang ◽  
Zhi Qiang Fu
Keyword(s):  
Support System ◽  
Concrete Structure ◽  
Environmental Temperature ◽  
Mechanical Performance ◽  
Live Load ◽  
Curing Time ◽  
Reinforced Concrete Frame ◽  
Construction Period ◽  
Concrete Frame ◽  
Test Models

Research for mechanism of concrete structure interacting with formwork support by manufacturing 2 test models of two-layer and single-span reinforced concrete frame at laboratory,and analysis interaction performance between concrete structure and formwork support and the influence of construction period,curing time of concrete and load on mechanical performance of formwork support system during the construction period.Research data shows:formwork support system interacted with concrete structure is a linear system when live load applied is smaller then crack load calculated according to mechanical indicators of loading-age concrete;load applied by formwork support system decreases with develop of curing time of concrete and removal of bottom support and construction period extension;it is also effected by environmental temperature.

Isolated Structures Research and Comparative with Traditional Seismic Structures

2012 ◽  
Vol 594-597 ◽  
pp. 1734-1739
Author(s):  
Min Yao ◽  
Tie Ying Li
Keyword(s):  
Base Isolation ◽  
Design Method ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Reinforced Concrete Frame ◽  
Maximum Displacement ◽  
Concrete Frame ◽  
Rare Earthquake ◽  
Traditional Structures ◽  
Nonlinear Time History

This paper introduces the concept and design method of the base isolation structure, through the SAP2000 software to analyze 6-story reinforced concrete frame for nonlinear time-history analysis, comparison of isolated and non-isolated structure's maximum displacement, acceleration under frequent earthquake and the maximum displacement, acceleration of isolation structure under rare earthquake. The results show that the isolated structure have a much better seismic responding than the traditional structures.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

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