Guard Post Load and Base Connection

IBC 1607.8.1 puts a 200 lb concentrated load AND a 50 plf uniform load on a guard, not concurrently -- so past 4 ft of post spacing the uniform case quietly takes over, and at 6 ft it is 300 lb, not 200. The real finding is where the trouble is: 300 lb at 36 in is 10,800 in-lb, which a 4x4 carries at 1,511 psi of bending, but the base connection has to resolve that same moment across maybe 4 in of bolt spacing -- 2,700 lb per side, NINE times the applied load. The lever arm collapsed from 36 in to 4 and multiplied the force by exactly that ratio, which is why deck guards fail at the rim joist and not at the post, and why lag screws into rim end grain are not acceptable. Allowable bending stress is an input (species, grade, NDS factors). Fastener, rim, and load-path capacity are not checked.

uniform load at a post = 50 plf x post spacing; governing load = max(200 lb concentrated, uniform at post), the two being non-concurrent; base moment = governing load x post height; post S = b d^2 / 6 on ACTUAL dimensions; required Fb = moment / S; connection couple force = moment / fastener lever arm; force multiplier = post height / lever arm.

IBC 1607.8.1 - handrails and guards designed for a 50 pound per linear foot uniform load and a 200 pound concentrated load, with the uniform load not assumed to act concurrently with the concentrated load. Intermediate rails, balusters, panel fillers, and guard infill carry a separate 50 pound concentrated load under 1607.8.1.1 and 1607.8.1.2, which this tile names but does not check. Everything after the load is statics.

The load values are short prescriptive sentences quoted throughout free code commentary and state adoptions. No table is reproduced, and no allowable stress is shipped - it is an input.

Estimate. AHJ and licensed professional govern.

Field names used by the API: post_height_in, post_spacing_ft, concentrated_lb, uniform_plf, post_b_in, post_d_in, allowable_fb_psi, connection_lever_in, uniform_at_post_lb, governing_load_lb, moment_inlb, section_modulus_in3, required_fb_psi, post_utilization, connection_force_lb, force_multiplier

• Load pair 50 plf uniform and 200 lb concentrated, NOT concurrentIBC 1607.8.1
• Crossover the uniform case governs past 200/50 = 4 ft of post spacingarithmetic on the two loads
• Base moment governing load x post height above the connectionstatics
• Connection couple moment / fastener lever arm; multiplier = height / lever armstatics
• Allowable stress an INPUT; species, grade, and NDS adjustment factors are not shippedstated scope limit
• Not checked fastener capacity, rim and blocking tension, load path, deflection, fatigue, other load directionsstated scope limit
• Infill the separate 50 lb load on balusters and panel fillers is named but not checkedIBC 1607.8.1.1 / 1607.8.1.2