scholarly journals ON THE CO-OPERATIVE ACTIONS OF FLOOR SYSTEM WITH MAIN STRUCTURE IN THROUGH TRUSS BRIDGES

1966 ◽  
Vol 1966 (130) ◽  
pp. 1-8
Author(s):  
Hiroyuki Kojima ◽  
Masao Naruoka
Keyword(s):  
Main Structure ◽  
Truss Bridges ◽  
Floor System

Evaluation of remaining fatigue life for riveted truss bridges

1998 ◽  
Vol 25 (4) ◽  
pp. 678-691 ◽  
Author(s):  
J D DiBattista ◽  
DEJ Adamson ◽  
G L Kulak
Keyword(s):  
Fatigue Life ◽  
Bending Moment ◽  
Accurate Estimate ◽  
Analytical Models ◽  
Truss Bridges ◽  
Fatigue Life Evaluation ◽  
Advanced Analysis ◽  
Pinned Connections ◽  
Floor System ◽  
Remaining Fatigue Life

The remaining fatigue life of riveted structures is a topic of considerable importance, particularly for owners of bridges. Improved methods for the estimation of the actual fatigue life of such structures are required in order to make their continued safe use possible while at the same time avoiding the expense of unnecessary repairs. To evaluate the fatigue life expectancy of a structural detail, it is necessary to obtain an accurate estimate of the stress history. Two analytical models are assessed through comparison with measured strains taken from a bridge in service. The results illustrate that a simple model with pinned connections is adequate for the determination of stresses in truss members and that more advanced analysis methods give only marginal increases in accuracy. Stresses in the floor system are most accurately predicted by a model that has full bending moment continuity between connected members. Standard and advanced methods of fatigue life evaluation are discussed and are then implemented in the evaluation of the remaining fatigue life for components of the bridge. Comparison with the actual fatigue life of the components, which were obtained from laboratory experiments, shows that both prediction methods give reasonable estimates of the fatigue life.Key words: bridge, fatigue, rivets, steel, model, analysis.

Removal of Steel Tie Rods in a Segmental Tied Arch Floor System

2013 ◽  
Author(s):  
J. Lan ◽  
R. Gilsanz ◽  
M. Lo
Keyword(s):  
Tie Rods ◽  
Floor System

Simulation of steel–concrete composite floor system behavior at elevated temperatures via multi-hybrid metaheuristic framework

2021 ◽  
Author(s):  
Armin Morasaei ◽  
Aria Ghabussi ◽  
Soheila Aghlmand ◽  
Maziar Yazdani ◽  
Shahrizan Baharom ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
System Behavior ◽  
Hybrid Metaheuristic ◽  
Floor System

Influence of floor system on seismic behavior of RC buildings to forward directivity and fling-step in the near-fault region

Structures ◽  
2021 ◽  
Vol 30 ◽  
pp. 803-817
Author(s):  
Sayed Mahmoud ◽  
Ali Alqarni ◽  
Joseph Saliba ◽  
Amal H. Ibrahim ◽  
Magdy genidy ◽  
...  
Keyword(s):  
Seismic Behavior ◽  
Rc Buildings ◽  
Near Fault ◽  
Forward Directivity ◽  
Fling Step ◽  
Floor System ◽  
Fault Region

scholarly journals Model Predictive Control Strategies to Activate the Energy Flexibility for Zones with Hydronic Radiant Systems

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1195
Author(s):  
Ali Saberi Derakhtenjani ◽  
Andreas K. Athienitis
Keyword(s):  
Control Strategies ◽  
High Price ◽  
Electricity Prices ◽  
Peak Demand ◽  
Heating Systems ◽  
Electrical Grid ◽  
Demand Reduction ◽  
The Cost ◽  
Floor System ◽  
Radiant Floor Heating

This paper presents control strategies to activate energy flexibility for zones with radiant heating systems in response to changes in electricity prices. The focus is on zones with radiant floor heating systems for which the hydronic pipes are located deep in the concrete and, therefore, there is a significant thermal lag. A perimeter zone test-room equipped with a hydronic radiant floor system in an environmental chamber is used as a case study. A low order thermal network model for the perimeter zone, validated with experimental measurements, is utilized to study various control strategies in response to changes in the electrical grid price signal, including short term (nearly reactive) changes of the order of 10–15 min notice. An index is utilized to quantify the building energy flexibility with the focus on peak demand reduction for specific periods of time when the electricity prices are higher than usual. It is shown that the developed control strategies can aid greatly in enhancing the zone energy flexibility and minimizing the cost of electricity and up to 100% reduction in peak power demand and energy consumption is attained during the high-price and peak-demand periods, while maintaining acceptable comfort conditions.

Reliability of nonlinear stochastic controlled systems considering the dynamics of sensors and actuators

2021 ◽  
pp. 107754632110037
Author(s):  
Sun Jiaojiao ◽  
Xia Lei ◽  
Ying Zuguang ◽  
Huan Ronghua ◽  
Zhu Weiqiu
Keyword(s):  
Closed Loop ◽  
First Passage Time ◽  
Hamiltonian Function ◽  
Small Time ◽  
Kolmogorov Equation ◽  
Sensors And Actuators ◽  
First Passage ◽  
Controlled System ◽  
Main Structure ◽  
Controlled Systems

A closed-loop controlled system usually consists of the main structure, sensors, and actuators. The dynamics of sensors and actuators may influence the motion of the main structure. This article presents an analytical study on the first-passage reliability of a nonlinear stochastic controlled system under the consideration of the dynamics of sensors and actuators. The coupled dynamic equations of the controlled systems with sensors and actuators are first given, which are further integrated into a controlled, randomly excited, dissipated Hamiltonian system. By applying the stochastic averaging method for quasi-Hamiltonian systems, a one-dimensional averaged differential equation for the Hamiltonian function is obtained. The backward Kolmogorov equation associated with the averaged equation is then derived for the first-passage reliability analysis, from which the approximate reliability function and probability density of first-passage time are obtained. The accuracy of the proposed procedure is demonstrated by an example. A comparative analysis of the reliability of the system with/without sensors and actuators is carried out, which indicates that ignoring sensors and actuators will make underestimation of the reliability of the closed-loop system with small time. However, when time increases, there appears the opposite trend. Our findings provide a reference for control strategy design.

scholarly journals Development of Optimal Design Method for Steel Double-Beam Floor System Considering Rotational Constraints

2021 ◽  
Vol 11 (7) ◽  
pp. 3266
Author(s):  
Insub Choi ◽  
Dongwon Kim ◽  
Junhee Kim
Keyword(s):  
Optimal Design ◽  
Design Process ◽  
Design Method ◽  
Steel Beams ◽  
High Gravity ◽  
Double Beam ◽  
Iterative Analysis ◽  
Floor Systems ◽  
Optimal Design Method ◽  
Floor System

Under high gravity loads, steel double-beam floor systems need to be reinforced by beam-end concrete panels to reduce the material quantity since rotational constraints from the concrete panel can decrease the moment demand by inducing a negative moment at the ends of the beams. However, the optimal design process for the material quantity of steel beams requires a time-consuming iterative analysis for the entire floor system while especially keeping in consideration the rotational constraints in composite connections between the concrete panel and steel beams. This study aimed to develop an optimal design method with the LM (Length-Moment) index for the steel double-beam floor system to minimize material quantity without the iterative design process. The LM index is an indicator that can select a minimum cross-section of the steel beams in consideration of the flexural strength by lateral-torsional buckling. To verify the proposed design method, the material quantities between the proposed and code-based design methods were compared at various gravity loads. The proposed design method successfully optimized the material quantity of the steel double-beam floor systems without the iterative analysis by simply choosing the LM index of the steel beams that can minimize objective function while satisfying the safety-related constraint conditions. In particular, under the high gravity loads, the proposed design method was superb at providing a quantity-optimized design option. Thus, the proposed optimal design method can be an alternative for designing the steel double-beam floor system.

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