STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

508 Drilling and Well Completions
Mast and Derricks under Dynamic Conditions
1. Maximum rated static hook load for a specified number of lines to the
traveling block.
2. Hook load, wind load, vessel motions, and pipe setback in combination with
each other for the following:
a. Operating with partial setback.
b. Running casing.
c. Waiting on weather.
d. Survival.
e. Transit.
Substructures
1. Maximum rated static hook load, if applicable.
2. Maximum rated pipe setback load.
3. Maximum rated static load on rotary table beams.
4. Maximum rated combined load of setback and rotary table beams.
Substructure under Dynamic Conditions
1. Maximum rated static hook load.
2. Maximum rated pipe setback load.
3. Maximum rated load on rotary table beams.
4. Maximum rated combined load of setback and rotary table beams.
5. All ratings in the section titled “Mast and Derricks under Dynamic Conditions.”
Design Loadings
Derricks and masts are designed to withstand some minimum loads or set of
loads without failure. Each structure shall be designed for the following
applicable loading conditions. The structure shall be designed to meet or exceed
these conditions in accordance with the applicable specifications set forth herein.
Derrick-Stationary
Base
1. Operating loads (no wind loads) composed of the following loads in
combination:
a. Maximum rated static hook load for each applicable string up condition.
b. Dead load of derrick assembly.
2. Wind load without pipe setback composed of the following loads in
combination:
a. Wind load on derrick, derived from maximum rated wind velocity
without setback (minimum wind velocity for API standard derrick sizes
10 through 18A is 93 knots, and for sizes 19 through 25 is 107 knots).
b. Dead load of derrick assembly.
3. Wind load with rated pipe setback composed of the following loads in
combination:
a. Wind load on derrick derived from maximum rated wind velocity with
setback of not less than 93 knots.
b. Dead load of derrick assembly.