Analysis on the Impact of the Backstays Forms on the Performance of Inclined Tower Cable-Stayed Bridge

2014 ◽  
Vol 533 ◽  
pp. 127-134
Author(s):  
Bo Lei ◽  
Ying Zhao Lv ◽  
Wei Ren
Keyword(s):  
Mechanical Property ◽  
Dynamic Property ◽  
Bending Moment ◽  
Contrastive Analysis ◽  
Visual Effect ◽  
Cable Stayed Bridge ◽  
Cable Force ◽  
Static Performance ◽  
The Difference ◽  
The Impact

In order to study the differences between spaces twisted backstay inclined tower cable-stayed bridge and conventionally cable-arranged cable-stayed bridge in mechanical property, this paper, taking a single-stay inclined tower space twisted backstays cable-stayed bridge as the study project, adopting FEM by changing the form of the backstays, makes a contrastive analysis on the difference between space twisted backstays cable arrangement (TBCA) and fan-shaped backstays cable arrangement (FBCA) in such aspects as static performance, dynamic property and stability. Some conclusions are concluded: the TBCA is easy to cause such problems as uneven distributed cable force, larger girders bending moment and stress; the integral rigidity of TBCA is less than that of FBCA; in stability, these two differ little, etc. As far as the overall comparison is concerned, TBCA is basically rational from the point of stress. However, while obtaining a certain visual effect, its mechanical property decreases somewhat.

scholarly journals PC Cable-Stayed Bridge Main Girder Shear Lag Effects: Assessment of Single Cable Plane in Construction Stage

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yan-feng Li ◽  
Xing-long Sun ◽  
Long-sheng Bao
Keyword(s):  
Bending Moment ◽  
Main Beam ◽  
Shear Lag ◽  
Distribution Law ◽  
Element Analysis ◽  
Cable Stayed Bridge ◽  
Action Point ◽  
Cable Force ◽  
Beam Section ◽  
Cable Forces

A model test and finite element analysis were conducted in this study to determine the distribution law of shear lag effect in the main beam section, a box girder, during the cable-stayed bridge construction process. The experimental and theoretical results were compared in an example of loading the control section. The stress value of the cable tension area of the main beam upper edge was found to markedly change when tensiling the cable force and was accompanied by prominent shear lag effect. After a hanging basket load was applied, the main beam of certain sections showed alternating positive and negative shear lag characteristics. The shear lag distribution law in the box girder of the single-cable-plane prestressed concrete cable-stayed bridge along the longitudinal direction was determined in order to observe the stress distribution of the girder. The results show that finite element analysis of the plane bar system should be conducted at different positions in the bridge under construction; the calculated shear lag coefficient of the cable force acting at the cable end of the cantilever reflects the actual force. In the beam segments between the cable forces, the shear lag coefficient determined by the ratio of the bending moment to the axial force reflects the actual stress at the cable force action point. In the midspan beam section between the action points of cable forces, the shear lag coefficient of the bending moment reflects the actual stress. The section shear lag coefficient can be obtained by linear interpolation of the beam section between the cable action point and the middle of the span.

Optimization of Stay Cables in the Double-Set Arch Pylon Cable-Stayed Bridge

2014 ◽  
Vol 711 ◽  
pp. 495-498
Author(s):  
Shi Xiang Hu ◽  
Wen Gang Ma ◽  
Min Luo
Keyword(s):  
Bending Moment ◽  
Original Design ◽  
Finite Element Software ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Bending Strain ◽  
The Difference ◽  
Negative Bending ◽  
Cable Forces

The determination of post-tensioning cable forces is one of the most important issues for the design of arch pylon cable stayed bridge. In this paper, the optimization module implemented in MATLB, together with the commercial finite element software MIDAS, were employed to evaluate the minimum bending strain energy of the bridge. After optimizing the cable forces, the bending moment of the pylons were bigger than the values of original design. The bending moment of the main arch pylon within 55m to 70m height increased by 7280 kN•m, and the bending moment of the auxiliary arch pylon within 30m to 60m height increased by 3926 kN•m .The stress of the pylons was still far below the allowance value when the obtained cable forces were applied. However, for the girder, the difference between the maximum positive and maximum negative bending moments due to dead load can be lessened greatly by the application of the obtained cable forces. The results obtained revealed that the method presented could make full use of cable forces and lead to optimal structural performance.

Research on Alignment Control of Cable-Stayed Bridge during Construction

2014 ◽  
Vol 716-717 ◽  
pp. 465-469
Author(s):  
Jin Jun Liang ◽  
Ke Wei Zhai ◽  
Jun Fan ◽  
Chun Le Shi
Keyword(s):  
Root Cause ◽  
Cable Stayed Bridge ◽  
Cable Force ◽  
Correction Program ◽  
The Difference

Measured values of alignment deviate significantly from the predicted ones partially of a cable-stayed bridge before closure. The root-cause was analyzed and a correction program was proposed in this paper. Unreliable anchoring and instable deformation of hanging basket resulted from the difference between hanging basket structure and construction requirements are the main cause. It is difficult to adjust cable force under cantilever state and it is feasible to adjust cable force and height after the bridge is setup.

Study on Natural Rubber Quality of Micro-Cut Tapping with Gas-Stimulation

2013 ◽  
Vol 834-836 ◽  
pp. 175-179
Author(s):  
Kai Dian Wang ◽  
Mao Fang Huang ◽  
Chun Liang Yang ◽  
Zong Qiang Zeng ◽  
Zhi Xiong Liang ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Natural Rubber ◽  
Protein Content ◽  
Dynamic Property ◽  
Control Group ◽  
Vulcanized Rubber ◽  
The Difference

The natural rubber samples produced by conventional tapping methods were used as a control, then analyzed the dry rubber property of natural rubber, the dynamic property and Physical & mechanical property of vulcanized rubber using Rubber processing analyzer and Thermogravimetric Analyze the difference between the properties of dry rubber and vulcanized rubber produced by Micro-cut Tapping with Gas-stimulation. The results indicated that the tensile strength, tear strength elastic modulus of dry rubber that produced by Micro-cut Tapping with Gas-stimulation are respectively 20%, 7% lower than the control. The protein content of dry rubber materials produced by Micro-cut Tapping with Gas-stimulation is 16.7% higher than control group.

Evaluation of the impact of public investment programs on social and economic performance of territories

2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena
Keyword(s):  
Bayesian Modeling ◽  
Positive Impact ◽  
Public Investment ◽  
Difference In Differences ◽  
The Public ◽  
Export Activity ◽  
Regional Investment ◽  
The Difference ◽  
The Impact ◽  
Development Institution

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.

The Use of Multimedia and its Impact on Bangladeshi EFL Learners at Tertiary Level

2020 ◽  
Vol 4 (2) ◽  
pp. 150
Author(s):  
Farzana Sharmin Pamela Islam
Keyword(s):  
Language Learning ◽  
Academic Writing ◽  
Teaching And Learning ◽  
English Language ◽  
Capital City ◽  
Tertiary Level ◽  
Language Classroom ◽  
The Difference ◽  
The Government ◽  
The Impact

As 21st century is the era of modern technologies with different aspects, it offers us to make the best use of them. After tape recorder and overhead projector (OHP), multimedia has become an important part of language classroom facilities for its unique and effective application in delivering and learning lesson. Although in many parts of Bangladesh, a South Asian developing country, where English enjoys the status of a foreign language, the use of multimedia in teaching and learning is viewed as a matter of luxury. However, nowadays the usefulness and the necessity of it are well recognized by the academics as well as the government. The study aims to focus on the difference between a traditional classroom void of multimedia and multimedia equipped classrooms at university level by explaining how multimedia support the students with enhanced opportunity to interact with diverse texts that give them more in-depth comprehension of the subject. It also focuses on audio-visual advantage of multimedia on the students’ English language learning. The study has followed a qualitative method to get an in-depth understanding of the impact of using multimedia in an English language classroom at tertiary level. For this purpose, the data have been collected from two different sources. Firstly, from students’ written response to  an open ended question as to their comparative experience of learning  lessons with and without multimedia facilities; and secondly, through  observation of English language classes at a private university of Dhaka, the capital city of Bangladesh. The discussion of the study is limited to  the use of multimedia in English language classroom using cartoons, images and music with a view to enhance students’ skills in academic writing, critical analysis of image and critical appreciation of music. For this purpose, cartoons in English language, images from Google and music from You Tube have got focused discussion in this paper.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals Soil Moisture Dynamics in Response to Precipitation and Thinning in a Semi-Dry Forest in Northern Mexico

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 105
Author(s):  
Argelia E. Rascón-Ramos ◽  
Martín Martínez-Salvador ◽  
Gabriel Sosa-Pérez ◽  
Federico Villarreal-Guerrero ◽  
Alfredo Pinedo-Alvarez ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Management ◽  
Water Availability ◽  
Dry Forest ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Northern Mexico ◽  
The Difference ◽  
The Impact ◽  
Moisture Dynamics

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.

scholarly journals 216. Are Automatic Antimicrobial Stop Orders an Effective Stewardship Tool for Urinary Tract and Intra-Abdominal Infections?

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S110-S110
Author(s):  
Christina Maguire ◽  
Dusten T Rose ◽  
Theresa Jaso
Keyword(s):  
Urinary Tract ◽  
Antimicrobial Therapy ◽  
Source Control ◽  
Clostridioides Difficile ◽  
Days Of Therapy ◽  
Before And After ◽  
The Difference ◽  
Tract Infections ◽  
Length Of Therapy ◽  
The Impact

Abstract Background Automatic antimicrobial stop orders (ASOs) are a stewardship initiative used to decrease days of therapy, prevent resistance, and reduce drug costs. Limited evidence outside of the perioperative setting exists on the effects of ASOs on broad spectrum antimicrobial use, discharge prescription duration, and effects of missed doses. This study aims to evaluate the impact of an ASO policy across a health system of adult academic and community hospitals for treatment of intra-abdominal (IAI) and urinary tract infections (UTI). ASO Outcome Definitions ASO Outcomes Methods This multicenter retrospective cohort study compared patients with IAI and UTI treated before and after implementation of an ASO. Patients over the age of 18 with a diagnosis of UTI or IAI and 48 hours of intravenous (IV) antimicrobial administration were included. Patients unable to achieve IAI source control within 48 hours or those with a concomitant infection were excluded. The primary outcome was the difference in sum length of antimicrobial therapy (LOT). Secondary endpoints include length and days of antimicrobial therapy (DOT) at multiple timepoints, all cause in hospital mortality and readmission, and adverse events such as rates of Clostridioides difficile infection. Outcomes were also evaluated by type of infection, hospital site, and presence of infectious diseases (ID) pharmacist on site. Results This study included 119 patients in the pre-ASO group and 121 patients in the post-ASO group. ASO shortened sum length of therapy (LOT) (12 days vs 11 days respectively; p=0.0364) and sum DOT (15 days vs 12 days respectively; p=0.022). This finding appears to be driven by a decrease in outpatient LOT (p=0.0017) and outpatient DOT (p=0.0034). Conversely, ASO extended empiric IV LOT (p=0.005). All other secondary outcomes were not significant. Ten patients missed doses of antimicrobials due to ASO. Subgroup analyses suggested that one hospital may have influenced outcomes and reduction in LOT was observed primarily in sites without an ID pharmacist on site (p=0.018). Conclusion While implementation of ASO decreases sum length of inpatient and outpatient therapy, it may not influence inpatient length of therapy alone. Moreover, ASOs prolong use of empiric intravenous therapy. Hospitals without an ID pharmacist may benefit most from ASO protocols. Disclosures All Authors: No reported disclosures

Arterial Stiffness Assessed by Cardio-Ankle Vascular Index in Patients With Abdominal Aortic Aneurysm and Its Alterations After Treatment

2021 ◽  
pp. 153857442110232
Author(s):  
Spyridon N. Mylonas ◽  
Konstantinos G. Moulakakis ◽  
Nikolaos Kadoglou ◽  
Constantinos Antonopoulos ◽  
Thomas E. Kotsis ◽  
...  
Keyword(s):  
Arterial Stiffness ◽  
Surgical Repair ◽  
Open Repair ◽  
Abdominal Aortic ◽  
Gender And Age ◽  
Baseline Values ◽  
The Difference ◽  
The Impact ◽  
Repair Group

Purpose: The aim of the present study was to investigate a potential difference on the arterial stiffness among aneurysm patients and non-aneurysm controls, as well as to explore potential changes between patients treated either with endovascular or open repair. Materials and Methods: A 110 patients with an infrarenal AAA were prospectively enrolled in this study. Fifty-six patients received an EVAR, whereas 54 patients received an open surgical repair. Moreover, 103 gender and age-matched subjects without AAA served as controls. The cardio-ankle vascular index (CAVI) was applied for measurement of the arterial stiffness. Results: CAVI values were statistically higher in the AAA patients when compared with control subjects. Although at 48 hours postoperatively the CAVI values were increased in both groups when compared to baseline values, the difference in CAVI had a tendency to be higher in the open group compared to the endovascular group. At 6 months of follow up the CAVI values returned to the baseline for the patients of the open repair group. However, in the endovascular group CAVI values remained higher when compared with the baseline values. Conclusion: Patients with AAAs demonstrated a higher value of CAVI compared to healthy controls. A significant increase of arterial stiffness in both groups during the immediate postoperative period was documented. The increase in arterial stiffness remained significant at 6 months in EVAR patients. Further studies are needed to elucidate the impact of a decreased aortic compliance after stentgraft implantation on the cardiac function of patients with AAA.

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