News & Views, Volume 49 | Code Compliance and the Modular Construction Trend

News & Views, Volume 49 | Code Compliance and the Modular Construction Trend: What Manufacturers Need to Know to Comply with Building Codes

By:  Andy Coughlin, PE, SE

News & Views, Volume 49 | Code Compliance and the Modular Construction Trend

The modular construction industry is projected to grow globally at an annual rate of 6.9%, outpacing the growth of traditional construction.1  Modular construction has many advantages over traditional building methods, including improved quality control and shorter project durations. Factory-built systems are constructed in controlled environments with equipment and materials that are not feasible at congested job sites, and project schedules can be shortened when factory work and field work are performed in parallel.

However, modular projects may stumble without proper forethought: when fabrication takes place in a factory away from the jobsite, the building officials, inspectors, and engineers can have less oversight and less recourse to implement changes if issues are discovered in the field.  Code compliance may also be an issue when systems are designed by factory engineers rather than the engineer of record.  To mitigate these potential pitfalls, careful planning is required at the start of the project.

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News & Views, Volume 49 | The 4th Dimension- Lifecycle Assessment of Critical Structures

News & Views, Volume 49 | The 4th Dimension: Lifecycle Assessment of Critical Structures

By:  Dan Parker, PE

News & Views, Volume 49 | The 4th Dimension- Lifecycle Assessment of Critical Structures

By analytically simulating the steps in the construction process, including the sequence of concrete placements, and tracking the history of the material behavior starting from initial placement, the potential for cracking is evaluated by comparing the time dependent stress and strains to the concrete cracking resistance and capacity.

Aging Infrastructure Issues

The infrastructure in the United States is aging and, whether publicly or privately owned, significant resources are required to repair, replace, or modernize it.  Due to the high costs associated with these efforts, owners need to identify structures with high risk-of-failure consequences and find the most cost-effective solutions for rehabilitation.  High consequence infrastructure includes:

  • Highway and railway bridges,
  • Roadways for intra and interstate transportation,
  • Dams, locks, and levees for flood control and cargo transportation,
  • High rise business, apartment, and condominium towers, and
  • Power generation and distribution facilities for Nuclear, Fossil and Hydro utilities.
News & View, Volume 47 | Aircraft Impact Assessments for NUSCALE Power

News & Views, Volume 47 | Aircraft Impact Assessments for NUSCALE Power

By:  Eric Kjolsing, Ph.D., PE

From 2015 to 2019 Structural Integrity Associates, Inc. (SI) worked with News & View, Volume 47 | Aircraft Impact Assessments for NUSCALE PowerNuScale Power,LLC. to develop structural details for and perform aircraft impact assessments of NuScale’s SMR Reactor Building.  The assessments were based on finite element analyses of various strike scenarios stemming from NEI 07-13 guidance.  ANACAP, a proprietary SI concrete constitutive model, was used in the finite element analyses.  Among other capabilities, the ANACAP model can capture multi-axial tensile cracking, compressive crushing with strain softening, and crack dependent shear stiffness.

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News & View, Volume 46 | Adding Value Through Test Informed Modeling- Hydro Structures

News & Views, Volume 46 | Adding Value Through Test Informed Modeling: Hydro Structures

By: Eric Kjolsing and Dan Parker

News & View, Volume 46 | Adding Value Through Test Informed Modeling- Hydro StructuresIn 2018, Structural Integrity Associates (SI) supported a utility in the structural assessment of a submerged concrete intake tower.  The tower is nearly a century old and was investigated as part of the utility’s periodic maintenance program. 

The assessment required the generation of an analysis model that accounted for both the structure and the surrounding water.  When accounting for fluid effects, a typical analysis approach is to develop a fluid-structure interaction (FSI) model that explicitly accounts for the interaction between the surrounding water and concrete tower.  However, this modeling approach is expensive both in terms of (a) cost, due to the increased effort needed in generating the model and (b) schedule, due to the increased analysis run time.  In lieu of developing an FSI model, SI implemented an alternative numerical approach to model the effects of the water and justified the approach through physical testing of the in-situ structure.

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News & View, Volume 45 | Improved Asset Management Through Test Informed Analysis

News & Views, Volume 45 | Improved Asset Management Through Test Informed Analysis

News & View, Volume 45 | Improved Asset Management Through Test Informed AnalysisBy:  Eri Kjolsing

Introduction
Structures may experience unforeseen operating environments or site-specific hazards leading to changes in the structure’s performance, safety, and longevity.  These changes often prompt asset owners to undertake analysis efforts to ensure satisfactory structural performance for the updated conditions. However, conventional analyses that fail to capture the true behavior of a structure can lead to inaccurate analysis results, causing owners to make less than ideal asset management decisions.  Structural Integrity (SI) is uniquely positioned to pair our dynamic characterization and advanced structural analysis capabilities to generate a better structural model.  SI vibration experts use impact testing, forced vibration, or ambient excitation sources, along with proprietary signal processing software, to non-destructively characterize the dynamic behavior of structural systems.  This characterization is used to inform advanced structural analyses by SI analysis experts to provide more accurate results related to operational improvements, damage location, and retrofits.

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News & View, Volume 44 | The Impact of the ASCE 7-16 Standard on Seismic Design and Certification of Equipment

News & Views, Volume 44 | The Impact of the ASCE 7-16 Standard on Seismic Design and Certification of Equipment

By:  Matt Tobolski

News & View, Volume 44 | The Impact of the ASCE 7-16 Standard on Seismic Design and Certification of EquipmentThings change, that’s just a fact of life. But when it comes to engineering codes and standards, change can be confusing, frustrating and expensive. As it relates to seismic design and certification of equipment, it is beneficial to understand the impact of code changes early to begin incorporating requirements in new equipment design, product updates and in the certification process.

One of the main structural design codes used in the United States and abroad, American Society of Civil Engineering (ASCE) 7, undergoes revisions on a five-year cycle. These revisions are based on input from committee members, building officials, interested parties and academia with the goal of ensuring specific performance objectives are achieved as well as incorporating lessons learned from practice. With the increase in enforcement of seismic certification provisions over the past 10 years, there has been a noticeable increase in industry lessons learned. The updates to the seismic provisions in ASCE 7-16 relating to equipment design and certification can primarily be attributed to these lessons learned.

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News & View, Volume 43 | Advanced Structural Analysis

News & Views, Volume 43 | Advanced Structural Analysis

By:  Eric Kjolsing & Philip Voegtle

News & View, Volume 43 | Advanced Structural AnalysisThe sophistication of structural analysis has evolved side-by-side with computing and graphics technology.  Structural engineers have at their fingertips very powerful software analysis tools that assist them in evaluating very large and complex structures for stability, suitability, and code adequacy.  The tools themselves vary in complexity in proportion with the engineering analysis required of them – the most complex and unique engineering problems requiring the most advanced analysis tools. Structural Integrity is a leader in advanced structural analysis (ASA), utilizing state-of-the-art software and material science expertise to solve an array of structural and mechanical problems. 

Structural analysis, in its most basic definition, is the prediction of the structural performance of a given structure, system, or component to prescribed loads, displacements, and changes in temperature.  Common performance characteristics include material stresses, strains, forces, moments, displacements and support reactions.  The results from a structural analysis are typically compared to acceptable values found in design codes.  Meeting the design code acceptance criteria ensures a design that protects the public’s health, safety, and welfare.

ASA extends this basic definition of structural analysis to one-of-a-kind problems where the acceptance criteria may not be well defined.  Since loads, material behavior, or the structure itself can go beyond the scope of basic design codes, ASA requires an in-depth understanding of modeling techniques, software limitations, and non-linear material behavior.  In ASA, sophisticated finite element analysis solvers are utilized to gain a detailed understanding of a system’s non-linear mechanical behavior, providing a full three-dimensional view of the critical stresses and strains in a loaded system.

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