38 BULLETIN 115, U. S. DEPARTMENT OF AGRICULTURE. 



"A"-FRAME GATES. 



A great many of the wooden lateral and check gates of the West 

 have utilized the "A" frame in the setting of all posts and braces in 

 the main channel of the flume forming the body of the structure. 



The gross opening between side walls is broken up into bays by 

 "A" frames embracing the guides for the shutters and the necessary 

 braces to support the closed shutters. These frames also carry the 

 operating platform or footwalk which acts as a strut in taking the 



Fig. 9. — A typical "A" frame construction for headgate or checkgate as connected to drop, 

 California Development Co., California. 



thiust of the side walls and helps to maintain the spacing of the 

 frames at the top. A typical construction of the frames and details 

 of the general arrangement of members are shown in figure 9. The 

 pressure of the water is transmitted downward to the floor, braces 

 being set normal to the gate face and bearing against stubs. The 

 larger structures have the floor spiked to joists which rest on mud 

 sills as shown in figure 9. Small ones have the floor spiked direct to 

 the sills. For such gates the braces go through the floor and are 

 spiked to the sill. The "A" frames against the side walls are modi- 



