Structural Engineering Institute Research Articles

Mentoring in the oil and gas industry

This paper is about the mentoring of graduate engineers in the oil and gas industry. The paper starts by defining what measurable success should look like for graduates, and outlines a 5-year plan leading to professional membership of Institution of Civil Engineers (ICE). Key steps en route are defined as technical competency, ICE membership, understanding the business and technical excellence. The author and other senior professionals developed two uniquely appropriate training courses, one at graduate entry level and the other at advanced level. These courses were used to train many graduates and other engineers in the essential skills and techniques of oil and gas structural engineering. The courses were produced and delivered freely, in the spirit of ‘learned society’ and ‘passing on the faith’ and were tremendously well received. References include recent ICE and Institution of Structural Engineers proceedings papers around the topic of ‘what should be taught in structural engineering design?’. Most of the literature comes from the academic side; this paper comes from a practitioner’s perspective. The principles involved can be readily applied to all branches of civil engineering.

DoD Research and Criteria for the Design of Buildings to Resist Progressive Collapse

The collapse of conventional/nonhardened structures was a concern of the U.S. Department of Defense (DoD) for years before the collapse of the World Trade Center (WTC) towers during the terrorist attacks on September 11, 2011 (9-11), owing to the bombings of the Murrah Federal Building in Oklahoma City, the U.S. embassies in Africa, and the U.S. Marine barracks in Lebanon. Since 9-11, motivated by the lack of any meaningful U.S. progressive collapse design requirements, DoD has worked with the civilian community on a number of significant efforts to improve the design of buildings to resist disproportionate collapse. The DoD efforts have included laboratory and field experiments, numerical simulations, and development of design requirements. Synergy and coordination with the civilian community resulted in combined programs with the General Services Administration, guidance and feedback provided by the ASCE Structural Engineering Institute (SEI) Committee on Disproportionate Collapse Standards and Guidance (DCSG) and its members, and adoption of some European civilian approaches to progressive collapse design. A significant result of the DoD effort was the creation of Unified Facilities Criteria (UFC) 4-023-03, Design of Buildings to Resist Progressive Collapse. The approaches employed in UFC 4-023-03 are currently being evaluated and modified for civilian applications by the SEI DCSG committee. The development and underlying approaches used in UFC 4-023-03 are briefly summarized in this paper, as are the previous DoD laboratory and field tests and numerical simulations.

Special Issue: Commemorating 10 Years of Research since 9/11

Special Issue: Commemorating 10 Years of Research since 9/11

The reuse of structural components and materials

This sustainability briefing prepared by the Institution of Structural Engineers' Sustainable Construction Panel discusses the reuse of structural components and material.

Influence of the Adhesive on the Load-Carrying Capacity of Glued Laminated Timber Members in Fire

Design models for timber structures in fire usually take into account the loss in cross-section due to charring and the temperature-dependent reduction in strength of timber. For bonded timber elements like glued laminated timber beams it is assumed that the adhesive used does not influence the resistance of structural timber beams significantly. To investigate the fire resistance of bonded timber elements a comprehensive research project is currently in progress at the Institute of Structural Engineering of ETH Zurich, Switzerland. The aim of this research project is the development of a simplified design model for the fire resistance of bonded structural timber elements taking into account the behavior at elevated temperature of the adhesive used. This paper presents experimental analyses and results of first calculations performed on the influence of the adhesive on the load-carrying capacity of glued laminated timber members in fire. It is shown that the temperature-dependent material properties of the adhesive used in the bondline of glued laminated timber beams have small influence on the shear resistance. For the investigated timber beams failure occurs mainly due to exceeding the bending moment resistance. Because of the steep temperature gradient in timber beams during fire exposure the temperature in the inner region of the cross-section is rather low; hence the shear capacity in the bondline between the different lamellas is still sufficient. However, in case of finger jointed lamellas of glued laminated timber beams, the influence of adhesive used in the finger joints is more significant and has to be considered. Tensile tests at elevated temperatures on finger jointed specimens confirmed the significant influence of the adhesive used.

Fire safety of multistorey timber buildings

Fire safety is the main precondition for the use of wood for multistorey timber buildings and is therefore an important criterion for the choice of material for buildings. The Institute of Structural Engineering at ETH Zurich has accomplished several research projects on the fire behaviour of timber structures over the past 15 years. The research projects aimed at supplying basic data and information on the safe use of timber, in particular for multistorey buildings. Further novel fire design concepts and models have been developed based on extensive theoretical studies, element and full-scale testing as well as a large statistical database on fires in timber. The better knowledge in the area of fire design of timber structures from the research projects, combined with technical measures, especially sprinkler and smoke detection systems, as well as well-trained and equipped fire brigades allow the safe use of timber and a wider field of application of timber for buildings. As a result the Swiss fire regulations of 2005 allow the use of timber structures in multistorey medium-rise residential buildings with up to six storeys. Many other countries have also liberalised the use of timber for buildings or introduced fire regulations that allow for the use of timber on the basis of performance. This paper describes the background of the design concept assumed for multistorey medium-rise buildings. It further presents an overview of two novel calculation models for the verification of the separating function of wall-and-floor timber assemblies as well as for the fire resistance of timber connections.

전단 보강이 없는 FRP RC보의 전단강도 예측

There are many problems in application of FRP reinforcing bars as shear reinforcement, since bending of FRP bars is not a feasible process on construction site. Even though FRP bars can be manufactured in bent shape, they have lower strength at bent location. However, there are no serious problems to use FRP bars as flexural reinforcement. Plates or slabs like bridge decks, in general, do not need shear reinforcements. These types of members with FRP flexural reinforcement have lower shear strength than those with conventional steel flexural reinforcement. However, reliable process or equation for shear strength estimation of FRP reinforced concrete without shear reinforcement are not established, yet. In this study, predicted shear strength obtained from available design equations and assessment equations are compared with 211 experimental results. The results showed that among the current design codes, the Architectural Institute of Japan (AIJ) and the Institution of Structural Engineers (ISE) provided the best estimation. ACI 440.1R-06 provided conservative results with degree of dispersion similar to that of ISE. In addition, regression analysis on the collected experimental results was conducted to develop regression models. As a result, a new reliable shear strength equation was proposed.

Opportunities within change: looking beyond the immediate

Consulting engineer Norman Train became the 90th president of The Institution of Structural Engineers in January 2010. This is a summary of his inaugural address, in which he calls for civil and structural engineers to be more outward facing.

Performance of Infrastructure During the May 12, 2008 Wenchuan Earthquake in China

The Ms 8.0 earthquake that struck the southwestern Chinese province of Sichuan on May 12, 2008 left 69,227 dead. another 17,923 listed as missing, and 374,643 injured. The epicenter of the earthquake was located in Wenchuan County, triggering a fault rupture length of about 300 km. Having reached an earthquake damage intensity of XI, many towns along the fault line were severely destroyed. As part of the devastating damage inflicted by the earthquake disaster, the infrastructure in the area was severely affected by the main event and its aftershocks. Based on the findings of a post-earthquake reconnaissance field mission carried out by the Earthquake Engineering Field Investigation Team (The Institution of Structural Engineers, UK) and by the European Laboratory for Structural Assessment of the Joint Research Centre of the European Commission, and on research carried out upon completion of the field mission, the seismic performance of the infrastructure in the affected area is presented in this article. The work focuses on the description of infrastructure performance during and after the disaster, in particular of highway- and road-engineered structures, railway, airports, hydraulic engineering, waterworks, pipelines, electric facilities, communication systems, and broadcast facilities. The information and recommendations provided in this article will be useful for engineers who design or maintain infrastructure in similar earthquake risk regions.

Fragility Analysis Methodology for Performance-Based Analysis of Wood-Frame Buildings for Flood

This paper resulted from a Structural Engineering Institute of the American Society of Civil Engineers Special Project entitled Next Step for ASCE 16: Performance-Based Design of Wood Structures. In 2005 Hurricane Katrina demonstrated how damaging flood waters can be to residential structures. While life safety of the occupants is the most critical issue for residential buildings the financial (property) loss due to water damage is often extensive and can result in personal financial ruin. This paper presents the methodology including several illustrative examples for the design of wood-frame residential structures for flood. The methodology is based on probabilistic flood hazard as defined by the U.S. Federal Emergency Management Agency and provides a probabilistic measure of annualized loss or loss over the anticipated/expected lifetime of the building. The primary purpose of this information is to aid in the decision making process during planning, construction, or the retrofit process. The approach is based on known properties of wood and housing products, and when not available, reasonable interpretations/assumptions were used based on expert opinions of those in the wood and/or housing industry.

국내 CFRP 긴장재의 전달길이에 관한 실험적 연구

CFRP (carbon fiber reinforced polymer) 긴장재는 PC 강연선의 부식문제를 해결하기 위해 대안으로 사용될 수 있다. CFRP 긴장재를 콘크리트구조물에 적용하기 위해서는 부착강도, 전달길이, 정착길이와 같은 재료적 특성이 명확히 결정되어야 한다. 특히 프리텐션 콘크리트 부재에 CFRP 긴장재가 적용될 경우 전달길이는 긴장력 도입에 있어서 중요한 요소가 된다. 본 연구에서 개발된 CFRP 전달길이 및 정착길이를 산정하기 위해 프리텐션 보 9개를 제작하였다. 전달길이 실험결과, 긴장력 25%인 경우는 34D, 긴장력 50%인 경우는 55D로 측정되었고, 긴장력이 커지면 전달길이가 증가하는 것으로 나타났다. 시간경과에 따른 전달길이 변화를 살펴보면, 긴장력의 크기에 따라 시간경과가 전달길이에 영향을 주는 것으로 나타났다. 보강재 특성계수 산정 결과, 본 연구에서 개발된 CFRP 긴장재의 보강재-특성 계수 αt는 2.3으로 PS강연선 (αt= 2.4)과 비슷한 것으로 나타났다.

Erratum: “A Momentum Transfer Measurement Technique Between Contacting Free-Falling Bodies in the Presence of Adhesion” [Journal of Applied Mechanics, 2008, 75(1), p. 011016

The complete affiliation of the authors is the following:M. Benedetti Department of Materials Engineering and Industrial Technologies and Italian Institute of Nuclear Physics INFN, University of Trento, 38050 Trento, Italy e-mail: matteo.benedetti@ing.unitn.it D. Bortoluzzi Department of Mechanical and Structural Engineering and Italian Institute of Nuclear Physics INFN, University of Trento, 38050 Trento, Italy S. Vitale Department of Physics, University of Trento and Italian Institute of Nuclear Physics INFN, 38050 Trento, Italy

The Next Step for AF&PA/ASCE 16-95: Performance-Based Design of Wood Structures

The concept of improving building performance has, for all prac-tical purposes, always existed at what might be deemed the soci-etal level. If engineered systems do not perform as society andusers deem acceptable, these systems do not continue to be con-structed and are eliminated over time. The inadequate systems arereplaced by improved ones whose performance is expected to bemore acceptable to the stakeholders and to society. In moderntimes this evolution manifests itself as revisions and updates toprescriptive design codes, which typically are anywhere from oneto seven years apart.The impetus to formalize performance-based design PBDhas its roots in Housing and Urban Development’s “OperationBreakthrough” of the 1970s NBSIR 1977 whose goal was toenable product innovation via industry. However, the wood indus-try, particularly home building, did not fully embrace innovationsfor increased performance since they often resulted in highercosts. Subsequently, these higher costs were not tolerated by themarketplace and thus the innovations were not implemented. Arecent Structural Engineering Institute SEI special project en-titled “Keeping Pace with ASCE 7” examined the reliability in-dexes inherent in the ASCE16-95 standard ASCE 1996; Bulleit2006 . The ASCE 16-95 committee of the SEI of the AmericanSociety of Civil Engineers ASCE has the option to move be-yond load and resistance factor design LRFD and spearhead thenext generation of standards for wood design, specifically aperformance-based standard. Following the aforementioned SEIspecial project, the SEI/ASCE committee on Reliability-basedDesign of Wood Structures embarked on a two-year specialproject entitled “The Next Step for AFP 2 continued occupancy; 3injury/life safety; 4 general structural integrity; and 5 manage-able loss/damage. Each discussion will address the hazard char-acterization, performance descriptors that align with the fiveperformance levels, model complexity required for analysis, de-sign procedure verification, and how these performance-basedanalyses can be extended to design. This discussion order is sum-marized in Fig. 1.Performance-based design has been defined in a variety ofways, including an engineering approach based on: 1 specificperformance objectives and safety goals of building occupants,owners, and the public; 2 probabilistic or deterministic evalua-tion of hazards; and 3 quantitative evaluation of design alterna-tives against performance objectives. However, PBD does notprescribe a specific technical solution Ellingwood 1998 . Perhapsa more practical definition, related to seismic design, is that givenby Nathan Gould of ABS Consulting: “PBSD Performance-Based Seismic Design is the seismic design methodology of thefuture. It allows the design team to work together to determine theappropriate levels of ground motion and performance objectives

Briefing: Sustainability expertise: key to the future of the construction professions

The relationship between construction professionals and their clients is changing radically. Graham Owens, who became the 89th president of the institution of Structural Engineers in January 2009, says new competencies in sustainability are needed if professionals are to retain their value.

Performance-Based Design of Residential Wood-Frame Buildings for Flood Based on Manageable Loss

The Structural Engineering Institute of the American Society of Civil Engineers Committee on the Reliability-Based Design of Wood Structures recently completed a special project entitled “The next step for ASCE 16: Performance-based design of wood structures.” This paper presents the methodology and several illustrative examples of the design of residential wood-frame buildings for flood. The control variable of interest is losses in terms of either U.S. dollars or percent of construction costs. To do this, assembly-based vulnerability is coupled with existing durability data for wood and wood-based products; and when not available, logical assumptions were required. A series of illustrative examples are shown with various mitigation strategies applied to investigate the change in loss fragilities, and subsequently, economic risk if the fragility is recoupled with the flood hazard curve. The method is shown to work efficiently and the results are logical, thus it may find application by aiding developers, land-use planners, engineers, and potentially owners of wood-frame buildings in their design and retrofit decisions.

Field investigation on the performance of building structures during the 12 May 2008 Wenchuan earthquake in China

A devastating earthquake struck the southwestern Chinese province of Sichuan on 12 May 2008, leaving 69,227 dead and 374,643 injured, with 17,923 people still missing five months after the main event. The epicentre of the earthquake was located in Wenchuan County, which triggered a fault rupture length of about 300 km, stretching northeast through Beichuan County and reaching Qingchuan County; many towns on both sides of the fault were severely damaged/destroyed, reaching an earthquake damage intensity of XI. This paper presents the findings of a post-earthquake reconnaissance field mission carried out by the Earthquake Engineering Field Investigation Team (The Institution of Structural Engineers, UK) and by the European Laboratory for Structural Assessment of the Joint Research Centre of the European Commission, through the description of the damage sustained by three of the towns that suffered the largest levels of devastation: Yingxiu Town of Wenchuan County, Beichuan Town of Beichuan County, and Hanwang Town of Shifang City. The work focuses on the description of building performance during and after the disaster, in particular of reinforced concrete frame, reinforced concrete confined masonry, unreinforced and unconfined masonry, industrial, local vernacular and historical buildings. The information and recommendations provided in this paper will be useful for future engineering applications in similar earthquake risk regions.

High Frequency Testing Facility for Stay Cables and Tendons

Fatigue is an important cause of failure in mechanical components and structures that are subjected to repeated loads. The testing of structural components under cyclic loading constitutes one of the most important fields of experimental mechanics. The testing of specimens with 2 to 20 million load cycles is only feasible for small specimens, and not for large structural elements. Usually, conventional servo-hydraulic testing machines are used; thus, time to carry out the experiments as well as the energy consumption increase dramatically with specimen size. A new approach to the testing of large structural elements by taking advantage of the resonance effect is shown in this paper. For example, a fatigue experiment on a stay cable for a bridge takes 3 to 4 weeks by using conventional servo hydraulic controlled jacks. The approach developed at the Institute for Structural Engineering at Vienna University of Technology reduces testing periods by a factor of 20 to 50 and the required energy input for a fatigue test by a factor of more than 1000. A testing unit dimensioned for a static tensile load up to 20 000 kN and an upper load for fatigue tests up to 10 000 kN was built at the Vienna University of Technology in 2006.

Editorial: Structural risk

A SPECIAL PUBLICATION OF THE INSTITUTION OF CIVIL ENGINEERS WITH THE INSTITUTION OF STRUCTURAL ENGINEERS The purpose of this special issue is to present reviews of the latest research thinking about the risk, reliability and vulnerability of civil engineering structures. Some researchers argue that structural risk is a mature discipline. The personal view of the guest editor (and not necessarily of the guest contributors to this issue) is that, while it has made strong advances, much more development is required before it can smoothly be incorporated into practice. On the human scale, I estimate that it is about 16 years old: strong and growing up fast but still lacking maturity. All of the papers are aimed at nurturing that important development which will eventually ease the topic into mainstream practice. In that respect all of the papers are intended to be of interest to practitioners.

Women reach the top in civil and structural engineering

There is no reason why women cannot now reach the highest levels in Brtain's construction industry, says Sarah Buck, who recently became the first female president of the Institution of Structural Engineers.

Briefing: Women reach the top in civil and structural engineering

There is no reason why women cannot now reach the highest levels in Brtain's construction industry, says Sarah Buck, who recently became the first female president of the Institution of Structural Engineers.