scholarly journals Establishing the Optimal Solution for Obstacle Crossings. Application for Bridge Km.14+162 Placed on the Bypass of Bistrita City

2017 ◽  
Vol 13 (1) ◽  
pp. 12-20
Author(s):  
Radu Adrian Iordanescu
Keyword(s):  
Cross Section ◽  
Concrete Slab ◽  
Mathematical Optimization ◽  
Optimal Solution ◽  
Optimization Techniques ◽  
Point Of View ◽  
Steel Beams ◽  
Technical Solution ◽  
Reinforced Concrete Slab ◽  
Local Road

Abstract The Bistrita city bypass crosses obliquely at km 14+162 the Bistrita river and a local road. In the area where the bridge is situated the river has a width of about 50.00m and the local road has 5.00m, being located at 12.00m from the bank of Bistrita. The bridge should provide a roadway that is 7.80m wide and two sidewalks of 1.50m. The challenge is to design a bridge that allows the crossing of the two barriers (the river and the local road) in the most efficient way possible from an economical point of view, but in such a way that both the geometrical constraints and the design requirements contained in the family of the European standards Eurocodes are respected. In order to achieve this goal, the author has investigated the design situation by comparing different possible technical solutions, by conducting a series of parametric studies and by utilizing mathematical optimization techniques. Following these investigations a 100.00m long bridge resulted. The superstructure is a continuous beam with three spans: 20.00m + 60.00m + 20.00m and consists of a composite steel - concrete deck. The deck cross section is composed of two steel beams with variable height and a reinforced concrete slab disposed on top. This configuration of the superstructure leads to the development of negative reaction forces in the bearings located at the end points of the deck. The study has covered 8 key steps as follows: - Establishing the technical solution. - Establishing the number and the length of the spans. - Setting the static scheme. - Determining the optimal cross section of the steel beams. - Setting longitudinal beam geometry. - Establishing the number of beams in the cross section. - Determining the optimal mounting order of the concrete slabs. - Establishing the optimal type and distribution of the bearing devices.

Serviceability Assessment of Composite Footbridge Under Human Walking and Running Loads

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Faraz Sadeghi ◽  
Ahmad Beng Hong Kueh
Keyword(s):  
Concrete Slab ◽  
Model Verification ◽  
Human Walking ◽  
Steel Beams ◽  
Vibration Source ◽  
Design Standards ◽  
Reinforced Concrete Slab ◽  
Codes Of Practice ◽  
Current Design ◽  
Vibration Responses

Footbridge responses under loads induced by human remain amongst the least explored matters, due to various uncertainties in determining the description of the imposed loadings. To address this gap, serviceability of an existing composite footbridge under human walking and running loadings is analyzed dynamically in this paper employing a finite element approach. The composite footbridge is made-up of a reinforced concrete slab simply supported at two ends on top of two T-section steel beams. To model the walking and running loads, a harmonic force function is applied as the vibration source at the center of the bridge. In the model verification, the computed natural frequency of footbridge exhibits a good agreement with that reported in literature. The vibration responses in terms of peak acceleration and displacement are computed, from which they are then compared with the current design standards for assessment. It is found that the maximum accelerations and displacements of composite footbridge in presence of excitations from one person walking and running satisfy the serviceability limitation recommended by the existing codes of practice. In conclusion, the studied footbridge offers sufficient human safety and comfort against vibration under investigated load prescription.

Theoretic-Strength Concept of a Model Describing the Destruction of the Corner Part of a Slab-Column Structure

2015 ◽  
Vol 240 ◽  
pp. 225-231 ◽  
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Laboratory Tests ◽  
Concrete Slab ◽  
Load Capacity ◽  
Limit Load ◽  
Traditional Theory ◽  
Load Step ◽  
Reinforced Concrete Slab ◽  
Column Structure

The paper presents a proposed theoretical-strength destruction model of the corner of a slab-column structure at 1:2 scale. The theoretical destruction model was developed on the basis of laboratory tests of a reinforced concrete slab with the dimensions 4000×4000×100 mm. The assumptions of the proposed theoretical model were based on a traditional theory of behaviour of reinforced concrete constructions. The method for calculating the strength of reinforced concrete sections is based on interaction graphs of the load capacity NRd, MRd,x and MRd,y. The calculation method takes into account the influence of changes in the shape of the cross-section of the analysed element on its limit load capacity in every load step.

scholarly journals The calculation of anchors in steel-concrete overlaps with precast slab

2019 ◽  
Vol 97 ◽  
pp. 06022
Author(s):  
Alexander Tusnin ◽  
Alexey Kolyago
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Slab ◽  
Element Model ◽  
Calculation Model ◽  
Concrete Slabs ◽  
Steel Beams ◽  
Steel Beam ◽  
Practical Application ◽  
Reinforced Concrete Slabs

Reinforced concrete floors and steel beams are widely used in buildings and structures for various purposes. Reinforced concrete overlaps can be cast-in or precast of hollow-core slabs. The most effective floors in which the concrete slab is located in the compressed area of cross-section, in steel beams in the tension zone, and shifting forces, arising between concrete slab and the steel beam, are perceived by anchors. Precast slabs in comparison with cast-in ones have less labor-intensive performance, the beam spacing is equal to the span of reinforced concrete slabs, there are no intermediate beams in such overlaps, that allows to reduce the floor thickness. The inclusion of precast in steel-concrete cross-section requires joints with steel beams, which requires using of special anchors. Anchor perceives shear forces and ensures the joint operation of the plate and the steel beam. In addition, for beams with narrow flange, the anchor device can provide the required width of the support slabs. The calculation of the attachment points of the anchors to the steel beam is carried out using three variants of calculation methods, which allow to determine the forces acting on the anchor. For practical application, a wire-element model has been proposed and managed to get forces in a steel beam, slab and anchors the width of the slab recommended by the standards should be included in the calculation model.

Steel-Reinforced Concrete Floors With The Use Of Bent Steel Profiles

2020 ◽  
pp. 10-14
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Theoretical Research ◽  
Steel Beams ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Steel Reinforced Concrete ◽  
Advantages And Disadvantages ◽  
Concrete Strengthening

The issues of designing a steel-reinforced concrete floor using bent steel profiles are considered. The steel-reinforced concrete flooring consists of a monolithic reinforced concrete slab arranged on a removable formwork, and steel bent profiles. The removable formwork during the concreting process rests on steel beams without additional mounting posts in the floor span. Steel beams accept the weight of the formwork and concrete during the pouring, working on bending. After concrete strengthening, they mainly work on stretching as part of composite steel-reinforced concrete structure. The article has identified the advantages and disadvantages of steel-reinforced concrete flooring with the use of light steel thin-walled bent profiles. Checking the strength of the beam at the concreting stage and evaluating the load-bearing capacity of the floor after the concrete strength is set confirm the performance of this structure. Using the regulatory methodology for SP 266.1325800.2016, the area of implementation of steel and concrete flooring with CFS beams and the nomenclature of applied steel beams have been established. For practical application of the presented design, it is recommended to conduct experimental and theoretical research and develop engineering methods.

Realtime Rate of Penetration Optimization Using the Shuffled Frog Leaping Algorithm

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Ping Yi ◽  
Aniket Kumar ◽  
Robello Samuel
Keyword(s):  
Gamma Ray ◽  
Mathematical Optimization ◽  
Optimal Solution ◽  
Tooth Wear ◽  
Optimization Techniques ◽  
Complex Nature ◽  
Shuffled Frog Leaping Algorithm ◽  
Rate Of Penetration ◽  
Drilling Parameters ◽  
Shuffled Frog Leaping

The increasing complexities of wellbore geometry imply an increasing well cost. It has become more important than ever to achieve an increased rate of penetration (ROP) and, thus, reduced cost per foot. To achieve maximum ROP, an optimization of drilling parameters is required as the well is drilled. While there are different optimization techniques, there is no acceptable universal mathematical model that achieves maximum ROP accurately. Usually, conventional mathematical optimization techniques fail to accurately predict optimal parameters owing to the complex nature of downhole conditions. To account for these uncertainties, evolutionary-based algorithms can be used instead of mathematical optimizations. To arrive at the optimum drilling parameters efficiently and quickly, the metaheuristic evolutionary algorithm, called the “shuffled frog leaping algorithm,” (SFLA) is used in this paper. It is a type of rising swarm-intelligence optimizer that can optimize additional objectives, such as minimizing hydromechanical specific energy. In this paper, realtime gamma ray data are used to compute values of rock strength and bit–tooth wear. Variables used are weight on bit (WOB), bit rotation (N), and flow rate (Q). Each variable represents a frog. The value of each frog is derived based on the ROP models used individually or simultaneously through iteration. This optimizer lets each frog (WOB, N, and Q) jump to the best value (ROP) automatically, thus arriving at the near optimal solution. The method is also efficient in computing optimum drilling parameters for different formations in real time. The paper presents field examples to predict and estimate the parameters and compares them to the actual realtime data.

scholarly journals To determine the optimal size of the elements of complex overlap

2019 ◽  
Vol 97 ◽  
pp. 04048
Author(s):  
Vitaly Kuznetsov ◽  
Yulia Shaposhnikova
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Strength Characteristics ◽  
Steel Beams ◽  
Optimal Size ◽  
Optimal Parameters ◽  
Limit States ◽  
Reinforced Concrete Slab ◽  
Object Of Study ◽  
Center Cell

The article discusses the possibilities of optimizing the size of elements of reinforced concrete ceilings along. The optimization of the overlap consists in finding such parameters of the reinforced concrete slab, profiled flooring and steel beams, in which their strength is fully used. For ceilings with steel beams included, the dimensions of the sections of the elements and their strength characteristics are determined by the requirements of the limit states of the second group (deflections), and the calculation of the forces in the slab and beams and strength calculations are performed taking into account the geometric and strength characteristics established from the calculation of deformations. To clarify the features of the calculation and verification of the main provisions, a numerical experiment was carried out, where the center cell of the steel concrete slab along metal rolling beams was selected as the object of study. Formulas are obtained for determining the forces using predetermined dimensions of the components of the overlap based on satisfying the requirements of the 2 groups of limit states. These studies can serve as a basis for further research on the search for optimal parameters of complex floors.

scholarly journals Windshield Defrost Simplified CFD Model

2019 ◽  
Vol 25 (25) ◽  
pp. 8-11
Author(s):  
Michal Schmid
Keyword(s):  
Layer Thickness ◽  
Combustion Engine ◽  
Ohmic Heating ◽  
Optimization Techniques ◽  
Point Of View ◽  
Computational Time ◽  
Technical Solution ◽  
Cfd Model ◽  
Simplified Approach ◽  
Hot Air

Abstract The windshield defrost system, in general, is a vehicle safety feature. Thus, its restricted by variety of directives. However, the OMEs’ benchmark targets could be even more demanding as the deicing process is in addition also part of passengers comfort. From vehicle design point of view the wind-shield defrost system is typically connected to HVAC unit (Heating, Ventilation and Air Conditioning). In the technical solution the windshield is heated via hot air convection. Nevertheless, other methods are becoming more and more popular, like directly heated glass by hot wire ohmic heating (heated glasses). The defrost CFD model should predict the ice layer thickness in time and space and in environmental conditions defined according to appropriate directives and technical solution. The accurate and fast modelling technique is essential part of a vehicle development, especially nowadays, where the optimization techniques area widely used and requires hundreds of simulations runs. Modelling requests are even increasing with modern pure electric vehicles (EVs), were the thermal and energy management is more demanding compared to the classical internal combustion engine (ICE) vehicles. The aim of the work is to verify possibility to model the ice layer thickness with simplified approach, which could be beneficial from computational time burden.

scholarly journals Experimental Investigation of Impact Concrete Slab on the Bending Behavior of Composite Bridge Girders with Sinusoidal Steel Web

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 273 ◽  
Author(s):  
Marcin Górecki ◽  
Krzysztof Śledziewski
Keyword(s):  
Steel Plate ◽  
Concrete Slab ◽  
Bending Moment ◽  
Bridge Girders ◽  
Steel Beams ◽  
Reinforced Concrete Slab ◽  
Plate Girders ◽  
Common Solution ◽  
Industrial Buildings ◽  
Corrugated Web

Until recently, steel plate girders with corrugated steel members were used primarily as poles and girders in the construction of industrial buildings. Currently, they are also being used in the construction of bridges. Compared to traditional steel and rolled girders, steel plate girders weigh less and are more stiff, while also having a neater appearance. In this paper, the results of an experimental study are present. The aim of the study was to determine the behavior of a bridge girder with sinusoidal web geometry when subjected to a bending moment. The study was focused on a composite steel and concrete structure with pin connections, which is currently the most common solution. Three near-real scale beams were subjected to bending tests. The study found that composite corrugated-web steel beams and non-composite corrugated-web steel beams showed similar forms of failure. A reinforced concrete slab did not prevent web stress concentration at the point of connection with the flange. Furthermore, the study indicates that corrugated steel webs in bridge girders can have a much smaller thickness (less than 8 mm) compared with the traditional solution.

Dimension and Frequency Profiles of Concrete Highway Bridges in New Madrid Region of Southeastern Missouri

1997 ◽  
Vol 1594 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ralph Alan Dusseau
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Highway Bridges ◽  
Ambient Vibration ◽  
Earthquake Hazards ◽  
Empirical Formulas ◽  
Reinforced Concrete Slab ◽  
Box Girder ◽  
Bridge Spans ◽  
New Madrid

The results of a study funded by the U.S. Geological Survey as part of the National Earthquake Hazards Reduction Program are presented. The first objective of this study was the development of a database for all 211 highway bridges along I-55 in the New Madrid region of southeastern Missouri. Profiles for five key dimension parameters (which are stored in the database) were developed, and the results for concrete highway bridges are presented. The second objective was to perform field ambient vibration analyses on 25 typical highway bridge spans along the I-55 corridor to determine the fundamental vertical and lateral frequencies of the bridge spans measured. These 25 spans included six reinforced concrete slab spans and two reinforced concrete box-girder spans. The third objective was to use these bridge frequency results in conjunction with the dimension parameters stored in the database to develop empirical formulas for estimating bridge fundamental natural frequencies. These formulas were applied to all 211 Interstate highway bridges in southeastern Missouri. Profiles for both fundamental vertical and lateral frequencies were then developed, and the results for concrete highway bridges are presented.

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