Study on Applicability of Double Layer Superimposed Primary Support Arch Cover Method for Large-Span Station in Upper Soft and Lower Hard Stratum

2021 ◽  
Author(s):  
Xinping Guo ◽  
Annan Jiang
Keyword(s):  
Double Layer ◽  
Large Span ◽  
Primary Support

Dynamic Instability of Spatial Structures under Typical Wind Flow

2011 ◽  
Vol 295-297 ◽  
pp. 1738-1741
Author(s):  
You Qin Huang ◽  
Ji Yang Fu
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Double Layer ◽  
Dynamic Instability ◽  
Wind Flow ◽  
Spatial Structures ◽  
High Wind ◽  
High Wind Speed ◽  
Large Span ◽  
Wind Flows

The mechanism of dynamic instability of large span spatial structures under high wind speed should be studied carefully, but it has seldom been done before. In this paper, a double-layer cylindrical reticulated shell under a typical wind flow is taken as an example to study the dynamic instability of large span spatial structures under wind flows. The interaction of the shell and the flow is ignored and unsteady wind forces on the shell are obtained from wind tunnel tests. The dynamic instability status of the shell is determined by the Budiansky-Roth criterion. The results show that the double-layer cylindrical reticulated shell will become dynamically instable under high wind speed.

scholarly journals Effectiveness of Different Connectors Used in DLGs

10.29007/dksw ◽  
2018 ◽  
Author(s):  
Mansi Mehta ◽  
Dipali Patel ◽  
Vishal A. Arekar
Keyword(s):  
Double Layer ◽  
Parametric Study ◽  
Three Dimensional ◽  
Total Weight ◽  
Frame Structure ◽  
Space Frame ◽  
Static Loads ◽  
Large Span ◽  
Varying Thickness ◽  
Space Frame Structure

Double-Layer Grid structures are three-dimensional pin-jointed structures, which are generally used for covering roofs having large span areas with the help of connectors. A Double Layer Grid structures are quite popular as the use of material can be reduced, easy to assemble and permits quicker construction. The weight of the structure depends on the member as well as connectors. The connectors contain 20-30% of total weight (by referring Lan, T.T. “Space frame structure”). In present study, two types of Connectors are used for analysis and for optimisation of structure. The aim of this study is to optimize the design and to get the effective connector. Solid connector and Hollow connector (with varying thickness) have been taken for parametric study, modelled in CREO and analysed using ANSYS 17.2. The results of stresses have been obtained under the static loads for comparison.

Research on the Synchronous Lifting Process Control of Large-Span Pre-Stressed Double-Layer Suspended Cable Roof

2014 ◽  
Vol 1065-1069 ◽  
pp. 1363-1368
Author(s):  
Chuan Qin Yao ◽  
Hai Bin Ma ◽  
Rong Bai ◽  
Shao Xin Jiang
Keyword(s):  
Process Control ◽  
Double Layer ◽  
Control Measures ◽  
Large Span ◽  
Common Reference ◽  
Suspended Cable ◽  
Key Points ◽  
The Common

Based on the project of Foshan International Home Expo City, this paper studied the control measures of the synchronous lifting process control of large-span pre-stressed double-layer suspended cable roof, and summarized some key points, which could be used as the common reference for the similar projects.

scholarly journals Experimental Analysis of Deformation Mechanics and Stability of a Shallow-Buried Large-Span Hard Rock Metro Station

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wei Li ◽  
Jiwen Bai ◽  
Kexian Li ◽  
Shijie Zhang
Keyword(s):  
Model Test ◽  
Large Scale ◽  
Hard Rock ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Three Dimensional Model ◽  
Metro Station ◽  
Large Span ◽  
Deformation Mechanics ◽  
Primary Support

Based on a certain Qingdao metro station, a large-scale three-dimensional model test has been carried out to investigate the stability of the surrounding rock masses (hard rock) and a large-span metro station under different excavation methods and technologies. The model test includes an entire section excavation, an arch-cover excavation, and a primary support arch-cover excavation. Compared with the entire section excavation, the primary support arch-cover method can effectively control the vault settlement and clearance convergence deformation of the surrounding rock masses, reducing them by 15–30%. The deformation itself goes through three stages: slow, abrupt, and stable. The excavation of the “middle hole” creates a drastic change in the tunnel vault during the arch-cover excavation; however, the timely application of supports can effectively constrain the range of disturbance caused by the excavation and weaken the degree of load agglomeration of the surrounding rock masses.

Research on Shallow Buried and Large-Span Tunnelling Undercrossing a Highway

2011 ◽  
Vol 90-93 ◽  
pp. 1748-1756
Author(s):  
Chun Yang Liu ◽  
Jian Li ◽  
Zhong Sheng Tan
Keyword(s):  
Ground Settlement ◽  
Safety Requirement ◽  
Large Span ◽  
Tunnel Section ◽  
Monitoring Result ◽  
Soil Settlement ◽  
Security And Reliability ◽  
Core Soil ◽  
Primary Support ◽  
Excavation Area

WenXiang tunnel ,one of the tunnels constructed for the ZhengXi Special passenger Railway in china. In this project we have carried out a series of research on optimizing the construction method for shallow and large-span tunnels in loess condition. According to the field monitoring of ground settlement, vault settlement and primary support stress of the tunnel section before tunnelling underneath the LianHuo Highway, the result indicates that soil settlement and primary support stress can not be controlled very well, and current construction program needs to be reformed since it can not meet construction safety requirement. Our synthetical analysis comprises the optimized methods have been used in construction, such as reducing excavation area, increasing excavation steps of pilot tunnel, reserving core soil, closing invert punctually, reinforcing primary support, etc. The security and reliability also has been verified by numerial analysis sofeware FLAC3D. From feedback of field implement and monitoring result, the effect of optimized method is significant; and all of these methods ensured this tough project implemented successfully. These results derived from our research are subject to a ceritain value that could be referred for future analogous project , in terms of controlling soil settlement and protecting surrouding building facilities.

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

A Survey on Crypto-Steganographic Schemes and A Use Case in Healthcare System

2019 ◽  
Vol 1 (2) ◽  
pp. 25-33
Author(s):  
Mei Ling Phang ◽  
Swee Huay Heng
Keyword(s):  
Social Networking ◽  
Information Sharing ◽  
Healthcare System ◽  
Double Layer ◽  
21St Century ◽  
Electronic Devices ◽  
Third Party ◽  
Use Case ◽  
Comparison Analysis ◽  
Information Assets

Information sharing has become prevalent due to the expansion of social networking in this 21st century. However, electronic devices are vulnerable to various kinds of attacks. Information might be disclosed, modified and accessed by an unauthorised third party which consequently leads to the breach of confidentiality, integrity and availability of the information. Therefore, it is of utmost importance to employ the technology of cryptography and steganography to protect information assets. Cryptography and steganography have weaknesses when they are working alone. Therefore, crypto-steganography, the combination of cryptography and steganography are introduced to overcome the weaknesses in order to provide a double layer of security and protection. This paper provides a general overview of steganography and cryptography as well as a comparison analysis of different crypto-steganographic schemes. A secure crypto-steganographic system for healthcare is then developed with the implementation and integration of the secure crypto-steganographic scheme proposed by Juneja and Sandhu. This healthcare system enables users to store and deliver message in a more secure way while achieving the main goals of both cryptography and steganography.

Translucent Glass Roofs For Large-Span Coverings

2019 ◽  
pp. 23-28
Keyword(s):  
Warm Season ◽  
Natural Light ◽  
Labor Costs ◽  
Main Bearing ◽  
Large Span ◽  
Glass Panels ◽  
Technical Properties ◽  
Internal Volume ◽  
Basic Approaches ◽  
Smoke Removal

The article deals with the issues of glass use in the enclosing structures of large-span coverings, which have such advantages as ensuring the penetration of natural light, tightness, minimum labor costs for repair and maintenance. Design shortcomings: the high cost, the need for protection of the internal volume against the penetrating sun rays in the warm season (hothouse effect); arrangement of devices for operation of a roof. The key technical properties and characteristics of glass panels and pane-glass sets, constructive decisions, including interface to the main bearing structures of a large-span covering are given. Peculiarities of their design with due regard for ventilation and smoke removal, a drainage of condensate, ways of fight against frosting and snow drifts on the roof are reflected. Features of the account of loadings, the basic approaches to their calculation are considered. Various design solutions for the spatial metal trussed systems with the original nodal connections are presented. Information on modern solutions of translucent roofs using glass for large-span coverings is given.

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