Model Code Design Force Provisions for Elements of Structures and Nonstructural Components

2000 ◽  
Vol 16 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Richard M. Drake ◽  
Leo J. Bragagnolo
Keyword(s):  
Building Code ◽  
Code Design ◽  
Structural System ◽  
Nonstructural Components ◽  
Model Code ◽  
Earthquake Design ◽  
Significant Change ◽  
New Buildings

With the publication of the 1997 Uniform Building Code ( UBC) and the 1997 NEHRP Recommended Provisions for the Seismic Regulations for New Buildings and Other Structures, there has been a significant change in the earthquake design force provisions for buildings, structures, elements of structures and nonstructural components. Engineers and architects need to become informed regarding a variety of earthquake design force provisions, primarily those published in the UBC and those developed as part of the NEHRP Provisions. Both sources provide design force provisions for the building structural system and separate design force provisions for elements of structures and nonstructural components. This paper describes the development, evolution, and application of the earthquake design force provisions for elements of structures and nonstructural components.

Review of NBCC earthquake-resistant design requirements for cladding connectors

1994 ◽  
Vol 21 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Michel Bruneau ◽  
Julie Mark Cohen
Keyword(s):  
Building Code ◽  
Nonstructural Components ◽  
Earthquake Resistant Design ◽  
Special Cases ◽  
Seismic Resistant ◽  
Limits Of Knowledge ◽  
Earthquake Design ◽  
Current Design ◽  
Design Requirements ◽  
Ductile Behavior

As a consequence of recent increases in the severity of seismic design force requirements in Canada, practicing engineers who design cladding connectors should be concerned with their seismic resistance. The current design requirements of the 1990 edition of the National Building Code of Canada for nonstructural components call for unduly high prescribed design forces for the cladding connectors without providing justification, commentary, or substantiation for this constraint, nor guidance on how this is to be achieved. This paper offers some rationalization of these stringent design requirements based on a review of their evolution, outlines some of the shortcomings of the current design approach, recommends possible abatements of the requirements in special cases, and points toward future directions and alternate philosophies for the design of cladding connectors. In particular, the following are recommended: (i) the scope of Part 4 of the National Building Code of Canada should be modified to specifically indicate that cladding connectors are to be designed by a professional engineer, (ii) the latest cladding-connector seismic-resistant design philosophy of the Structural Engineers Association of California should be incorporated into the National Building Code of Canada; (iii) a distinction should be made between out-of-plane and in-plane cladding-connector seismic-resistant design requirements; (iv) a commentary should be written on cladding-related seismic-resistant design issues to clearly state current philosophy, uncertainties, and limits of knowledge be included in the building code, and (v) standardized seismic-resistant cladding connectors be developed with capacities to meet prescribed levels of ductile behavior and interstory drifts and widely distributed to the profession. Key words: cladding, connectors, earthquake, design, code, seismic.

Major Changes in Concrete-Related Provisions-1997 UBC and Beyond

2000 ◽  
Vol 16 (1) ◽  
pp. 141-162
Author(s):  
S. K. Ghosh
Keyword(s):  
Seismic Design ◽  
Building Code ◽  
Earthquake Hazards ◽  
Structural Concrete ◽  
Seismic Codes ◽  
Evolutionary Changes ◽  
Reduction Program ◽  
Design Requirements ◽  
New Buildings ◽  
Made In

U.S. seismic codes are undergoing profound changes as of this writing. Changes from the 1994 to the 1997 edition of the Uniform Building Code (UBC) (ICBO 1994, 1997) are many and far-reaching in their impact. The 1997 edition of the National Earthquake Hazards Reduction Program (NEHRP) Recommended Provisions for Seismic Regulations for New Buildings (BSSC 1998) contains further evolutionary changes in seismic design requirements beyond those of the 1997 UBC. The latter document will form the basis of the seismic design provisions of the first edition of the International Building Code (IBC), to be published in the spring of 2000. This paper first discusses the major changes that have been made in the concrete-related provisions from the 1994 to the 1997 edition of the UBC. The paper gives background to these changes, provides essential details on them, and indicates how they have been or how they are going to be incorporated (at times with significant modifications) into the 1997 NEHRP Provisions and the 2000 IBC. The newly published ACI 318-99, Building Code Requirements for Structural Concrete (ACI 1999), is going to be adopted by reference into the 2000 IBC. This entails further changes in concrete-related provisions beyond the 1997 UBC. Some of the more important of these changes are discussed here. A small number of amendments and additions to the ACI 318-99 provisions are going to be included in the 2000 IBC. The more important of these are also outlined in this paper.

Background information for some of the proposed earthquake design provisions for the 2005 edition of the National Building Code of Canada

2003 ◽  
Vol 30 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Ronald H DeVall
Keyword(s):  
Structural Design ◽  
Building Code ◽  
Background Information ◽  
Load Path ◽  
Special Design ◽  
Load Paths ◽  
Irregular Structures ◽  
Earthquake Design ◽  
Importance Factor ◽  
Design Requirements

There are many changes proposed for the Earthquake Design Provisions of the 2005 edition of the National Building Code of Canada (NBCC). Among them are requirements for complete load paths, separation of stiff nonstructural elements, and the introduction of definitions of irregular structures and special design requirements associated with these irregularities. A new requirement for direction of loading is introduced, along with requirements for elements common to more than one lateral load resisting system. The effects of displacements are emphasized throughout the document, and revised provisions for drift limits are proposed. Revisions to the importance factor that integrate it into the proposed revised format for Part 4, Structural design, of the NBCC are given. Background information is presented.Key words: load path importance factor, irregular structures, direction of loading, special requirements, drift limits.

October 1871

2017 ◽  
Author(s):  
Thomas Leslie
Keyword(s):  
Building Code ◽  
American City ◽  
Similar Composition ◽  
Hard Times ◽  
The City ◽  
New Buildings

This chapter details the reconstruction of Chicago following the Great Fire. Chicago grew faster than any American city through the depression-scarred 1870s. By 1880 its population reached half a million, nearly doubling in size since the Fire. In 1879 just under 1100 new buildings were constructed in the city, but in 1883 there were over 4000. The city's building code, developed in the conservative years of the depression, came under increasing pressure as the motive to build higher returned with new investment. The emergence of the tall skyscraper was gradual, and the convergence of Chicago skyscrapers toward remarkably similar composition, proportions, and even detail occurred in several loosely defined steps between the end of the “hard times” around 1879 and the flourishing of what was called the “Chicago Style” or “Chicago Construction” of the late 1880s.

Probabilistic Seismic Loss Analysis for the Design of Steel Structures: Optimizing for Multiple-Objective Functions

2016 ◽  
Vol 32 (3) ◽  
pp. 1587-1605 ◽  
Author(s):  
Sanaz Saadat ◽  
Charles V. Camp ◽  
Shahram Pezeshk
Keyword(s):  
United States ◽  
Structural Response ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Earthquake Hazard ◽  
Economic Losses ◽  
Structural System ◽  
Nonstructural Components ◽  
Central United States

An optimized seismic performance-based design (PBD) methodology considering structural and nonstructural system performance and seismic losses is considered to optimize the design of a steel structure. Optimization objectives are to minimize the initial construction cost associated with the weight of the structural system and the expected annual loss (EAL), considering direct economic losses. A non-dominated sorting genetic algorithm method is implemented for the multi-objective optimization. Achieving the desired confidence levels in meeting performance objectives of interest are set as constraints of the optimization problem. Inelastic time history analysis is used to evaluate structural response under different levels of earthquake hazard to obtain engineering demand parameters. Hazus fragility functions are employed for obtaining the damage probabilities for the structural system and nonstructural components. The optimized designs and losses are compared for the structure located in two geographic locations: one in the central United States and another in the western United States.

Should we build better? The case for resilient earthquake design in the United States

2020 ◽  
pp. 875529302094418
Author(s):  
Keith A Porter
Keyword(s):  
Earthquake Engineering ◽  
The United States ◽  
Rating Systems ◽  
Economic Interests ◽  
The Us ◽  
Earthquake Design ◽  
Strength And Stiffness ◽  
Performance Based Earthquake Engineering ◽  
Real Estate Sales ◽  
New Buildings

America seems to have an earthquake investment gap, paying billions more annually on average to recover from earthquakes than it invests to prevent losses beforehand. Two large studies for Federal Emergency Management Agency (FEMA) and the US Geological Survey (USGS) offer insight into how well American buildings will resist future catastrophic earthquakes. They suggest that the public prefers new buildings to do more than to assure life safety, which has been the building code’s historic objective. They also suggest that greater resilience would better serve society’s economic interests. People expect to be safe in new buildings and the building code delivers safety. But people also want to use buildings after the Big One. America has a few options for meeting those expectations, including stronger, stiffer construction, with geographically optimized strength and stiffness. Greater strength and stiffness is not the only option to improve resilience, but such an approach offers the advantages that it could be implemented in practice by any structural designer without requiring additional technical expertise, software, of proprietary technology. It would produce a healthier economy and save society an average of $4 for every $1 of added cost. The savings cross property lines, benefiting tenants, owners, lenders, developers, and everyone who does business with them. The added cost would amount to approximately 1%, and experience in Moore, Oklahoma, shows that it would probably affect real estate sales and prices little or not at all. The solution addresses ethical considerations by responding to the public’s expectations for better performance and by optimizing utilitarian outcomes. Other options such as second-generation performance-based earthquake engineering, innovative technologies, and rating systems could complement this approach and further increase resilience.

CONSTRUCTION TECHNIQUES ON THE BOSPORUS REGION

2016 ◽  
Vol 10 (1) ◽  
pp. 155 ◽  
Author(s):  
Fatih Yazicioglu
Keyword(s):  
Structural Material ◽  
Historic Buildings ◽  
Structural System ◽  
Traditional Architecture ◽  
Coast Line ◽  
External Wall ◽  
Performance Requirements ◽  
Construction Techniques ◽  
New Buildings

The Bosporus is a unique place with its traditional architecture. The construction of new buildings along the Bosporus coast line are forbidden and only reconstructions of demolished original historic buildings are possible. Since 1984 legal authorities act different legislations about these reconstructions. Until 2005 the legislation gives permission for the usage of any structural material unless the overall appearance is the same as the original building. But after 2005 the legislation changed and the usage of original structural material became mandatory. The underlying reason of this is to protect the originality and authenticity of the Bosporus buildings both with their appearances and construction techniques. But the practical output became promoting the constructers for making the reconstructions without following the approved reconstruction projects or changing the reconstructions afterwards. In this paper structural system, external wall, window, and roof alternatives for reconstructions are compared and contrasted by evaluating the performance requirements. Examples of inappropriate reconstructions are documented and a tentative proposal is made for the reconstructions of the Bosporus region.

CASE STUDY OF SEISMIC EVALUATION AND STRENGTHENING OF EXISTING LOW-RISE REINFORCED CONCRETE BUILDING

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Amthal Hakim ◽  
Adnan Masri
Keyword(s):  
Reinforced Concrete ◽  
Shear Walls ◽  
Evaluation Process ◽  
Seismic Evaluation ◽  
Rc Structures ◽  
The Status ◽  
Earthquake Design ◽  
Bracing System ◽  
New Buildings

All new buildings nowadays have to be designed and executed to overcome any imposed type of loading (lateral/vertical). On a universal scale, the stock of buildings built before 1980’s is believed to be many times more than the number of newer buildings in most urban cities. In Beirut, as an example, a large proportion of Reinforced Concrete (RC) structures were constructed in the absence of mandatory earthquake design requirements, and unquestionably recognized as the type of construction most vulnerable to earthquakes. The performed research focused on how to evaluate the status of old building and how to design and execute the convenient seismic strengthening schemes. A case study has been selected to implement the evaluation process and design proposals. Conventional seismic upgrading technique has been assessed like the addition of shear walls in addition to more innovative approach which is the installation of steel bracing system. The strengthening schemes proposed aimed to create an ideal harmonization of the technical, economic and social aspects of the issue in hand. Analysis of the three structural systems (existing, modified with shear walls and with bracing systems) has been performed using the ETABS software including static equivalent, dynamic and pushover analyses. The research sorted out with a comparison between the systems based on different structural criteria followed by general recommendations and suggestions.

The Seismic Provisions of the 1997 Uniform Building Code

2000 ◽  
Vol 16 (1) ◽  
pp. 85-100 ◽  
Author(s):  
Robert E. Bachman ◽  
David R. Bonneville
Keyword(s):  
The United States ◽  
Site Amplification ◽  
Major Elements ◽  
Building Code ◽  
Ground Acceleration ◽  
Reliability Factor ◽  
Nonstructural Components ◽  
Source Effects ◽  
Story Drift ◽  
Soil Site

Currently the most widely accepted code regulations in the United States for seismic design of structures and nonstructural components are those found in the Uniform Building Code ( UBC). The UBC seismic requirements were significantly revised in the 1997 edition. Among the issues addressed in the UBC revisions are near-source effects and ground acceleration dependent soil site amplification factors for both short- and long-period structures. Also, the design force levels in the 1997 UBC are based on strength design rather than allowable stress design, as had been used previously. Other significant changes include introduction of a redundancy/reliability factor, a more realistic consideration of story drift and deformation compatibility, and new equations for equivalent static forces for both structural and nonstructural components. This paper traces the recent history of the code development and describes the major elements of the 1997 UBC seismic provisions.

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