Analysis of different cross-frame placements to enhance torsional irregular buildings against structural failure under earthquake bidirectional loadings: A case study

Design and certification of novel self-healing aerospace structures was explored by reviewing the suitability of conventional deterministic certification approaches. A sandwich structure with a vascular network self-healing system was used as a case study. A novel probabilistic approach using a Monte Carlo method to generate an overall probability of structural failure yields notable new insights into design of self-healing systems, including a drive for a faster healing time of less than two flight hours. In the case study considered, a mature self-healing system could be expected to reduce the probability of structural failure (compared to a conventional damage-tolerant construction) by almost an order of magnitude. In a risk-based framework this could be traded against simplified maintenance activity (to save cost) and/or increased allowable stress (to allow a lighter structure). The first estimate of the increase in design allowable stresses permitted by a self-healing system is around 8 per cent, with a self-healing system much lighter than previously envisaged. It is thought these methods and conclusions could have wider application to self-healing and conventional high-performance composite structures.

Download Full-text

Diagnostics of the structural failure of sports hall external wall layers

MATEC Web of Conferences ◽

10.1051/matecconf/201928402005 ◽

2019 ◽

Vol 284 ◽

pp. 02005

Author(s):

Leopold Kruszka ◽

Pawel Muzolf

Keyword(s):

Technical Condition ◽

The Other ◽

Diagnostic Process ◽

Construction Technology ◽

Structural Failure ◽

External Wall ◽

Aerated Concrete ◽

Structural Failures ◽

Construction Defects

The paper presents the diagnostics of the technical condition of the external layers of the sports hall walls. Structural failures related to construction defects themselves constitute a relatively small percentage (4.1% in 2017, 5.05% in 2014-2017 [1]), although the main reason for them is the lack of maintaining technological rigors (76.9% in 2017, 68.4% in 2014-2017 [1]). The presented and described case study of the technical condition of the newly built sports hall does not refer to structural failure, but to the reduction of the risk of that failure as a result of non-compliance with construction technology, in particular, in relation to the external walls. Contrary to the design, the walls of the sports hall were made of aerated concrete. According to the declaration of a designer, the contractor neither consulted the changes with the designer nor gain the acceptance of the designer for using aerated concrete instead of the primary proposed and designed brick structure. In addition, aerated concrete curtain walls with a height of about 4.5 m were made without any wall connectors. This resulted in a risk of a structure failure involving the collapse of its curtain walls. The technological requirements for the repairing of the elements of supporting walls as well as the diagnostic process of the other damaged finishing cladding of external walls are also provided in this paper.

Download Full-text

Use of Pushover Analysis for Predicting Seismic Response of Irregular Buildings: A Case Study

Journal of Earthquake Engineering ◽

10.1080/13632460902898308 ◽

2009 ◽

Vol 13 (8) ◽

pp. 1089-1100 ◽

Cited By ~ 29

Author(s):

Angelo D'Ambrisi ◽

Mario De Stefano ◽

Marco Tanganelli

Keyword(s):

Seismic Response ◽

Pushover Analysis ◽

Irregular Buildings

Download Full-text

Structural Safety Assessment of Marine Operations From a Long-Term Perspective: A Case Study of Offshore Wind Turbine Blade Installation

Volume 3: Structures, Safety, and Reliability ◽

10.1115/omae2019-96686 ◽

2019 ◽

Cited By ~ 1

Author(s):

Amrit Shankar Verma ◽

Zhen Gao ◽

Zhiyu Jiang ◽

Zhengru Ren ◽

Nils Petter Vedvik

Keyword(s):

Failure Probability ◽

Safety Assessment ◽

Routine Activity ◽

Structural Safety ◽

Offshore Wind Turbine ◽

Structural Failure ◽

Blade Root ◽

Extreme Response

Abstract A marine operation is a complex non-routine activity of limited duration carried out in offshore environment. Due to safety reasons, these operations are normally performed within specific sea state limits, which are derived from numerical modelling and analysis of hazardous events. In view of the uncertainties in the assessment of structural responses under stochastic environmental conditions, these limiting curves correspond to a target structural failure probability recommended in offshore standards (for example, 10−4 per operation as specified by DNV-GL). However, one of the main limitations is that these curves do not reflect site-specific safety assessment. The current paper presents a novel methodology for assessing the structural safety level of marine operations from a long-term perspective. The methodology includes estimation of extreme response distribution under all possible operational sea states (i.e. the operational domain under the limiting sea states) for a given offshore site and is compared to the response limit to obtain an average failure probability. A case study is also presented for a blade root mating process onto preassembled hub using a jack-up crane vessel and risk of impact between root and hub is considered critical. Global time-domain simulations are performed using multibody dynamics, and extreme value distributions for impact velocities are derived for different wind-wave conditions. The allowable impact velocity between the blade root and the hub is determined by an explicit finite element analysis of the damage at the blade root. Finally, the average failure probabilities considering the operational domain are obtained for four different European offshore sites and are compared to the target level of structural failure probability considered for the limiting sea states.

Download Full-text