Search results for "Structural Engineering"

Application of an energy model for fatigue life prediction of construction steels under bending, torsion and synchronous bending and torsion

2003

Abstract The paper contains a mathematical model of the material’s behaviour under cyclic loading taking into account the dynamics of the fatigue process, including the number of cycles to failure, induced by the mean stress value. The coefficients in the proposed model have been obtained from experimental tests under symmetrical and nonsymmetrical loading (with the stress ratio R =0). The proposed model has been used in order to modify an energy criterion with the aim of accounting for the influence of the mean stress on the fatigue life. The fatigue tests have been performed for structural steels 10HNAP and 18G2A subjected to cyclic bending, torsion and synchronous bending with torsion, b…

Assessing a Local Losses Evaluation Procedure for Low-Pressure Lay-Flat Drip Laterals

2014

In the past, several research experiments have focused on the hydraulic characterization of traditional drip irrigation systems, and different design methodologies have been proposed with the aim of achieving very high emitter discharge uniformity (EU). The increasing use of low-pressure lay-flat drip laterals, characterized by a thin-walled polyethylene pipe, makes necessary a specific determination of their hydraulic properties, aimed to a correct design of such systems. Here, the validity of an empirical local losses estimation model was assessed for five different commercial lay-flat drip tapes. Moreover, the errors in the maximum lateral lengths obtained for a fixed emitter uniformity,…

Fatigue Design Methodology for Large Mooring Chains Subjected to Out-of-Plane Bending

2014

The present paper presents a fatigue life prediction method for chains subjected to tension and Out-of-Plane-Bending (OPB). The investigation was carried out on a high strength mooring chain segment with a diameter of 165 mm and a steel quality R5. Such chains are used in mooring systems for large Floating Production Storage and Offloading (FPSO) units in harsh weather condition. Due to the fact that the mooring chains are pre-tensioned the wave induced displacements will introduce secondary bending effects about the weak axis in the chain links, particularly in the bilge hang-off area. In such chains both conventional tension fatigue and fatigue damage accumulation due to Out-of-Plane-Bend…

A Semiactive Vibration Control Design for Suspension Systems with Mr Dampers

2011

Published version of a chapter published in the book: Vibration Analysis and Control - New Trends and Developments. Also available from the publisher at: http://www.intechopen.com/source/pdfs/17688/InTech-A_semiactive_vibration_control_design_for_suspension_systems_with_mr_dampers.pdf. OA

Semiactive vibration control of nonlinear structures through adaptive backstepping techniques withH∞performance

2011

This article presents a new approach to the vibration mitigation problem in structures subject to seismic motions. These kinds of structures are characterised by the uncertainties of the parameters that describe their dynamics, such as stiffness and damping coefficients. Moreover, the dampers used to mitigate the vibrations caused by earthquakes are usually nonlinear devices with frictional or hysteretic dynamics. We propose an adaptive backstepping controller to account for the uncertainties and the nonlinearities. The controller is formulated in such a way that it satisfies an H∞ performance. It is designed for a 10-storey building whose base is isolated with a frictional damper (passive …

New Solution of Classical Hydraulic Jump

2009

This technical note, applying dimensional analysis and incomplete self-similarity, proposes a new functional relationship for the sequent depth ratio for hydraulic jumps over both smooth and rough horizontal beds. For the smooth bed condition, experimental measurements in the literature were used to calibrate the new relationship. For the rough bed condition the data of a previous investigation were used with new measurements carried out in a rectangular horizontal flume having a gravel bed. Finally, a generalized solution of the sequent depth ratio is proposed.

THE OPTIMUM SELECTION OF THE WINDOW SHADING LEVELS AND OF THE INDOOR VENTILATION RATES AS A DESIGN STRATEGY FOR BIOCLIMATIC COMMERCIAL BUILDINGS

1991

ABSTRACT Ventilation rates, shading level of windows and indoor air temperature are analyzed together in order to single out the optimum mix referred to the thermal comfort situations of thermally moderate commercial buildings. Thermal comfort is here taken into account by means of the Predicted Mean Vote ( Fanger, 1970 ). A short selection of graphs is proposed, able to provide the simultaneous view of the effects produced, on the PMV, by modifications of the above cited parameters. Graphs can be usefully adopted for the proper design of the glazed surfaces, especially for passive solar buildings.

Discussion of “EDR in Circular Channels” by Subhasish Dey

2002

Simplified flexural response of steel-fiber reinforced concrete beams

2008

In the present paper, an analytical model is proposed that is able to determine the flexural response of supported beams under four-point bending tests. Cases of normal strength reinforced concrete beams with longitudinal bars in the presence of reinforcing hooked steel fibers and transverse stirrups are considered. A simplified analytical model is presented that is able to calculate the load-deflection curves and the maximum and ultimate deflections occurring in the case of shear or flexure failures. In the case of shear failure, the maximum shear strength of the beams is evaluated by using a recent analytical expression proposed by the author able to account for the shear-to-moment intera…

Flower Roundabouts And Double-Lane Roundabouts: A Comparative Performance Analysis

2014

AbstractIn the paper, a choice criterion between flower roundabouts and double-lane roundabouts is proposed, focusing on operational benefits that can derive from one scheme over the other, and outlining a general framework for benefit-cost analysis. In order to assess operational benefits of innovative roundabouts over modern roundabouts, a comparative analysis was made. Capacity was estimated using gap-acceptance models. In detail, assuming the dichotomic shifted negative exponential distribution to model headways in circulating streams, the Hagring formula was adjusted to obtain entry capacity estimations at roundabout approaches where entering vehicles face one or two conflicting flows.…