RSPEC

Bulk Data Entry Specifies directional combination method, modal combination method, excitation direction(s), response spectra and scale factors.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
RSPEC	`RID`	`DCOMB`	`MCOMB`	`CLOSE`
	`DTISPEC1`	`SCALE1`	`X11`	`X12`	`X13`
	`DTISPEC2`	`SCALE2`	`X21`	`X22`	`X23`
	`DTISPEC3`	`SCALE3`	`X31`	`X32`	`X33`

Example 1

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
RSPEC	35	ALG	SRSS	1.0
	7	1.3	0.5	0.5	-1.

Example 2

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
RSPEC	35	SRSS	CQC	0.0
	7	1.3	0.5	0.5	-1.
	4	2.0	-2	-0.0	-1.
	2	17.	0.5	-2.5	-1.

Definitions

Field	Contents	SI Unit Example
`RID`	RSPEC identification number. Must be unique. No default (Integer > 0)
`DCOMB`	Method for directional combination. ALG (Default) Algebraic SRSS Square root of sum of squares.
`MCOMB`	Method for modal combination. ABS (Default) Absolute sum. SRSS Square root of sum of squares. CQC Complete quadratic combination. NRL Navy Research Laboratory's SRSS
`CLOSE`	Modal frequency closeness parameter. Default = 1.0 (Real)
`DTISPECi`	Response spectrum reference. A DTI,SPECSEL entry identification number. No default (Integer > 0)
`SCALEi`	Scale factor for excitation. No default (Real <> 0.0)
`Xij`	Components of a vector representing ground excitation i, j = 1..3

Comments

DTISPEC2/SCALE2/X21/X22/X23 and DTISPEC3/SCALE3/X31/X32/X33 are optional ground excitations for multi-directional excitation. The directions of excitation have to be orthogonal to each other and will be reported as error otherwise.
Refer to Response Spectrum Analysis in the User Guide for more details.