DESIGN DETAILS 



3-25 



in the load carrying members which meet at right angles to each other need not be high 

 for this connection to be a trouble-maker, because the reduction in load carrying area is 

 so great. The problem is magnified if the intervening member which must transmit the 

 load is made of fiberglass laminate, because this intervening member is being loaded in 

 the wrong direction, causing delamination, as was previously explained and indicated in 

 Fig. 3-1. A bolted connection is used to avoid this delamination. Note how the introduc- 

 tion of small brackets increases the area of load transfer considerably. 



TABLE 3-5 - STRESS CONCENTRATIONS IN BONDED JOINTS 



C - COMPRESS I ON 

 TENSION 



JOINT 



STRESS CONCENTRATION UNDER 



T C M 



OFFSET LAP 



DOUBLE BUTT LAP 



MODERATE 



MAJOR MAJOR 



DOUBLE BEVEL LAP 



Ml NOR MODERATE 



Ml NOR MAJOR 



BEVELLED I NSET LAP 



MODERATE Ml NOP MAJOR 



TRANSFER MEMBER 



HORI 20NTAL 

 LOAO CARRYING 

 MEMBER 



VERTICAL LOAD 

 CARRY I NG MEMBER 



ALTERNATE 

 POSI TION OF 

 BRACKET 



THROUGH BOLTS 



TO AVOID DELAMINATION 



OF TRANSFER MEMBER 



TRANSFER MEMBER 



AREA OF LOAD TRANSFER 



a. NQT ACCEPTABLE - SMALL AREA OF LOAD 

 TRANSFER 



1>. ACCEPTABLE - LOAD TRANSFERRED BY BOLTS, 

 BRACKET MAY BE USED ON ONE SIDE ONLY 

 AND MAY BE HORIZONTAL OR VERTICAL AS 

 SHOWN. 



Fig. 3-55. Knife Edge Crossing 



