38 BULLETIN" 115, U. S. DEPARTMENT OE 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. 
tin ust 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- 
