Impacts of Using Tubular Sections in Open Web Steel Joists

Open web steel joists are lightweight structural trusses used in place of I-beams to support long-span floors and roofs of open space buildings. Their slender geometry makes them highly efficient in resisting flexure, but susceptible to out-of-plane buckling in a failure mode known as lateral-torsional buckling. This failure can be avoided by running lateral bracing between joists called bridging or potentially by using tubular sections to build up the joists rather than angle sections. It is possible that a joist design using tubular cross-sections could require less bridging and prevent the need to use erection bridging for initial joist construction. Tubular sections provide good resistance to bending along with significantly higher resistance to torsion. While torsion resistance has little impact on capacity on small unbraced lengths, it has high impacts on large unbraced lengths. This thesis examines the structural characteristics of a tubular design for a 32LH06 joist layout and the results suggest a change to the joist cross-section to increase the joist efficiency. The findings indicate that a tubular design can provide required torsional stability while improving safety for installers

Cold-formed steel profiled decks topped with cementitious structural panels to enable fast floor construction of residential buildings

High efficiency floor systems satisfying structural and serviceability performance and providing ease of construction could significantly impact the quality and cost of buildings. Many of the traditional floor systems require cast-in-place concrete and most of the new floor systems are proprietary, resulting in additional costs. The FastFloor Residential project explores a new type of floor system that is non-proprietary and uses existing components to make a simple efficient design without any cast-in-place concrete. The prototype design uses two cold-formed steel profiled decks connected with self-drilling screws to form a cellular deck and topped with cementitious structural panels. Through a series of twelve four-point bending tests, the impact of fully and partially composite deck-to-structural panel connections are explored. This paper investigates how the deck and structural panel interaction impacts capacity, stiffness, and failure mode of the prototype floor system. The results have shown that using the structural panels could increase the ultimate strength up to 50%.Testing on a FastFloor Residential prototype has provided promising results. The structural panel and use of a close fastener spacing both show significant increase in capacity above steel only response. There is, however, significant analysis and testing that needs to be completed to make more significant conclusions regarding serviceability, strength, and the use of the prototype in diaphragms

Caswell, Hollis L., and Associates, The Changing Curriculum, pp 1-21 in their Curriculum Improvement in Public School Systems. New York: Bureau of Publications, Teachers College, Columbia University, 1950.

Reviews the history of U. S. curriculum to date; subsequent chapters discuss curriculum development and evaluation

Caswell, Hollis L, Emergence of the Curriculum as a Field of Professional Work and Study, pp. 1-11 in Helen F. Robinson, ed., Precedents and Promises in the Curriculum Field . New York: Teachers College Press, 1966. Reprinted pp. 26-31 in Edmund C. Short and George D. Marconnet, eds., Contemporary Thought on Public School Curriculum . Dubuque, IA: W. C. Brown, 1968.

Gives the history of currriculum as an emerging field of professional practice and study and identifies its several characteristics

Caswell, Hollis L., and Associates, Curriculum Improvement in Public School Systems . New York: Bureau of Publications, Teachers College, Columbia University, 1950.

Presents reports on several school systems engaged in curriculum improvement efforts

Caswell, Hollis L., Persistent Curriculum Problems, Educational Forum, 43(November, 1978), 99-110.*

Identifies three problems encountered during the author\u27s years of work in curriculum that still persist: the definition of the basics, procedures to improve the curriculum, and general education

Caswell, Hollis L., The Revisionist Historians and Educational Practice, pp. 29-30 in Laurel N. Tanner, ed., Papers of the Society for the Study of Curriculum History. University Park, PA: The Society, College of Education, Penn State University, 1981.

Tries to correct errors about curriculum history made by revisionist historians

Education in the elementary school

xvii, 406 hal.; 21 cm

Cold-formed steel profiled decks topped with cementitious structural panels to enable fast floor construction of residential buildings

High efficiency floor systems satisfying structural and serviceability performance and providing ease of construction could significantly impact the quality and cost of buildings. Many of the traditional floor systems require cast-in-place concrete and most of the new floor systems are proprietary, resulting in additional costs. The FastFloor Residential project explores a new type of floor system that is non-proprietary and uses existing components to make a simple efficient design without any cast-in-place concrete. The prototype design uses two cold-formed steel profiled decks connected with self-drilling screws to form a cellular deck and topped with cementitious structural panels. Through a series of twelve four-point bending tests, the impact of fully and partially composite deck-to-structural panel connections are explored. This paper investigates how the deck and structural panel interaction impacts capacity, stiffness, and failure mode of the prototype floor system. The results have shown that using the structural panels could increase the ultimate strength up to 50%.Testing on a FastFloor Residential prototype has provided promising results. The structural panel and use of a close fastener spacing both show significant increase in capacity above steel only response. There is, however, significant analysis and testing that needs to be completed to make more significant conclusions regarding serviceability, strength, and the use of the prototype in diaphragms