TENSILE LAP SPLICES PART 1: RETAINING WALL TYPE, VARYING MOMENT ZONE

AN INVESTIGATION OF THE STRENGTH OF CLOSELY SPACED LAP SPLICES IN RETAINING WALL STEMS IS REPORTED. SPLITTING TYPE FAILURES TYPICALLY OCCURRED, OFTEN STRIPPING THE ENTIRE COVER OFF THE SPLICES. THIS STUDY OF 32 SPECIMENS WITH #11 AND #8 BARS IS CONTINUING INTO 1969-1970. IT IS CONCLUDED IN PART A THAT THE 1965 AASHO SPECIFICATION FOR SPLICES DOES NOT PROVIDE AS SAFE GUIDE UNLESS IT IS SERIOUSLY MODIFIED. THE NECESSARY IMMEDIATE MODIFICATIONS ARE DEVELOPED FOR THE CASE OF 2 IN. CLEAR COVER, WITH A SPLICE LENGTH INCREASING AS LATERAL SPACING DECREASE AND THE PRESENT SPECIFICATION ADEQUATE ONLY FOR UNUSUALLY WIDE SPACINGS. IN PART B A TENTATIVE THEORETICAL TREATMENT OF LAP SPLICE LENGTH BASED ON THE SEVERAL OBSERVED TYPES OF SPLITTING FAILURE IS PRESENTED. ALTHOUGH THIS THEORY IS POTENTIALLY A CONSIDERABLE ADVANCE OVER PRESENT KNOWLEDGE, CERTAIN TRANSITION STAGES AND LIMITS MUST BE BETTER DEFINED BEFORE IT CAN BE USED WITH CONFIDENCE. A PORTION OF THE 1969-1970 PROGRAM IS DIRECTED TO THIS END. /AUTHOR/