Hello,
I am following the "Deck Overhang Loads" help page to input my deck overhang and construction loads into the "Deck Placement Sequence" window.
I am then double checking that my loads are creating the correct lateral moments using the equation below and the tables in the analysis "Construction Lateral Moment" report.
So far, so good - these unfactored moments exactly match what my hand calcs give me.
But then, when I go to check fl in the Constructibility code checker, I can't get it to match. I am even using a 1.5 load factor on the construction moment due to the AASHTO Article 3.4.2.1.
Can you confirm the load factors that are applied to the lateral moments when calculating the lateral flange stress for the constructibility checks?
Thanks
LL factor for Strength I during construction :
As per Article 3.4.2.1 “Unless otherwise specified by the owner, construction loads including dynamic effects (If applicable) shall be added in Strength Load combination I with a load factor not less than 1.5 when Investigating for Maximum force effects.”
For different stages of construction the program provides a default value of 1.75 which is greater than 1.5 and is conservative.
Also we have the user defined option where the user can input the Load factor value of 1.5 manually.
Vinay,
The loads in question are not vertical loads and therefore do not appear in the "Loads" window that you are showing.
This is the problem at hand - I do not know which load types (and therefore load factors) are being considered for the construction lateral loads.
Can you please provide me the load type of each "Deck Placement Sequence" load input?
Deck Overhang (kip/ft) = what load type?
Const (kip/ft) = what load type?
Fin. Machine (kips) = what load type?
I apologize for the incorrect screenshot.
Using Deck, Construction and finishing machine loads to compute moments M_lat that will be passed into the code checker with the appropriate factors applied based on the user selected Strength load combination.
For example the DC load factor applies to the deck load and the DW load factor applies to the construction loads and the finishing machine loads.
For example:
•W-Fact = DC( Deck) + DW(Const)•Ml_deck = (w-fact * Lb^2) / 12.0
Answer Verified By: Alex Spieler
Forgot to add this calculation.
Lateral flange bending stress fl calculation :
For top flange fl_top = (Ml-deck + Ml-fin) / Sy-top-flange For bottom flange fl_bot = (Ml-deck + Ml-fin) / Sy-bot-flange
Thank you for confirming those load types and the fl equation. I am now able to confirm the constructibility code checker stresses!
You are welcome.
I'm glad the issue is resolved.