Design of Partially or Fully Composite Beams, with Ribbed Metal Deck, Using LRFD Specifications
A Hindu saying states, "One picture is worth a thousand words (numbers)." With this optic in mind, the design aspects of steel-concrete composite beams using the recently adopted LRFD specifications 1 are analyzed critically and the significance of several parameters is brought out clearly. Charts are then constructed to facilitate the design of partially or fully composite beams using rolled-steel, wideflange sections of A36 steel or A572 Gr. 50 steel. The slab may be a composite metal deck slab with ribs perpendicular to the beam, a haunched slab or, simply, a flat soffit concrete slab. The charts cover both adequate and inadequate slabs. The charts provided are a valuable tool from the practical standpoint, and also familiarity with them should contribute to the student's and young engineer's overall feel of the composite beam design problem. The design charts given here complement the composite beam design tables provided in the LRFD manual.
Flexural Strength of Steel-Concrete Composite Beams
Tests on twelve single span and one two-span continuous, full scale composite beams are described, and the results evaluated. The investigation was concerned with determining the minimum number of shear connectors required for steel and concrete composite beams in buildings. A thorough examination of the ultimate strength of members was made. A criterion for the minimum shear connector requirement was derived based on the ultimate strength of the members. Relationships between the ultimate strengths of commonly used types of mechanical shear connectors and the ultimate strength of a composite beam are developed. The deflection of members is shown to be larger for beams with the minimum recommended shear connection as compared to theoretical bending deflections, and the magnitude of these deflections is discussed.
STUDY OF COMPOSITE BRIDGE STRINGERS, PHASE II
THE PHASE OF THE INVESTIGATION DESCRIBED IN THIS REPORT WAS DESIGNED TO STUDY THE BEHAVIOR OF COMPOSITE BRIDGE BEAMS AND TO CHECK THE VALIDITY OF PREDICTING THIS BEHAVIOR USING A RATIONAL NUMERICAL ANALYSIS WHICH HAS BEEN PROGRAMMED IN THE FORTRAN II LANGUAGE. EIGHT COMPOSITE BEAMS WITH WIDELY VARYING PROPERTIES WERE TESTED ALONG WITH SEVENTEEN COMPANION PUSHOUT SPECIMENS. VARIABLES INCLUDED' /A/ STEEL STRENGTH, /B/ SIZE, TYPE AND NUMBER OF SHEAR CONNECTORS, /C/ CONCRETE STRENGTH, AND /D/ TYPE OF CONCRETE /NORMAL AND LIGHTWEIGHT/. THE TEST BEAMS WERE GAGED TO MEASURE DEFLECTION, SLIP AND STRAIN AT VARIOUS LOCATIONS. A TWO- POINT CONCENTRATED LOAD WAS APPLIED IN SMALL INCREMENTS UP TO APPROXIMATELY WORKING LOAD, THEN RELEASED AND REAPPLIED UNTIL THE BEAMS FAILED. THE EXPERIMENTAL DATA WERE EVALUATED AND COMPARED WITH THE THEORETICAL BEHAVIOR PREDICTED FROM THE COMPUTER ANALYSIS. A DISCUSSION OF THIS ANALYSIS AND A PRINTOUT OF THE PROGRAM ARE APPENDED TO THE REPORT. TWO OF THE CONCLUSIONS WERE THAT 1. THE COMPUTER ANALYSIS WILL ADEQUATELY PREDICT THE BEHAVIOR OF FULL-SCALE COMPOSITE BEAMS, AND 2. THE BEHAVIOR OF COMPOSITE BEAMS UTILIZING EITHER LIGHTWEIGHT OR NORMAL-WEIGHT CONCRETE IN THE SLAB MAY BE PREDICTED EQUALLY WELL. /AUTHOR/