Span Rating of Solid-Sawn Deck Boards

Deck boards are key components in outdoor decks and balconies. The deck board market is shared primarily between solid-sawn and composite products. The focus of this article is solid-sawn wood deck boards, which are manufactured in North America as span-rated products following a policy promulgated by the American Lumber Standard Committee (ALSC). The latest revision of the ALSC span rating policy was approved in November 2020, and this article describes the technical basis for the changes. Distributed and concentrated design loads specified in the policy exceed building code minimum requirements. In addition, dynamic load amplification due to deck occupants is included in the new policy. Testing was performed to characterize the effects of partial fixity at joist supports caused by screw fasteners and was incorporated into the span rating methodology.

IMPROVING THE PRECISION OF FLOW-SENSITIVE LIFETIME ANALYSIS

Object lifetimes are a common source of bugs in C++ that can cause crashes, unexpected behavior, or even security vulnerabilities. Herb Sutter, the chair of the C++ standard committee proposed a flow-sensitive analysis to catch lifetime errors statically. Sadly, this analysis is prone to false positives unless the author follows some specific guidelines. We developed mitigations to eliminate some classes of false positives to make it easier to write conforming code. The first mitigation fixes a common false positive from a frequently used coding pattern by introducing local path-sensitivity. The second one is a filter based on reaching definitions and dominance algorithms to remove reports that might be the result of analyzing infeasible paths. We tested the effectiveness of the methods on the open source Google Fuchsia project.

Integrity Constraints in an Active Database Environment

This chapter surveys the interaction between active rules and integrity constraints. First, we analyze the static case following the SQL-1999 Standard Committee point of view which, up to date, represents the state of the art. Then, we consider the case of dynamic constraints for which we use a temporal logic formalism. Finally, we discuss the applicability, limitations and partial solutions found when attempting to ensure the satisfaction of dynamic constraints.

Implementing the ANSI Z-365 Standard for Control of Work-Related Cumulative Trauma Disorders

This panel will present an overview of the latest working draft of the ANSI Z-365 standard for control of work-related cumulative trauma disorders and discuss how both newly established and already successful ergonomics programs in large and small companies can utilize the consensus standard. The audience will have an opportunity to make inquiries to the ANSI standard committee chairs, discuss relevant technical aspects of the standard, exchange views about the proposed standard, and offer perspectives on the implementation of ergonomics programs in industry.