EQE Bulgaria Ltd, Sofia, Bulgaria
WALL TYPE 2
3. Packing - The joint into which the mortar is to be packed shall be damp but without freestanding water. The mortar shall be tightly packed into the joint in layers not
exceeding 1/4 inch (6.4mm) in depth until it is filled; then it shall be tooled to a smooth surface to match the original profile.
Structural Evaluation
The seismic analysis of the Emergency Generator Station/Building found several concerns in the existing lateral force-resisting system of the building. These concerns include the lack of a complete lateral resisting system and insufficient capacity in the existing lateral force-resisting system to comply with Reference 1. These concerns are described in the following paragraphs.
The lateral force-resisting system along the exterior wall at wall line A is insufficient to resist the expected lateral forces. A complete vertical lateral force-resisting system is required along line A using some of the existing vertical steel columns modified to accommodate new steel diagonal members. Strengthening of the steel roof diagonals is required to allow the elements to carry both compression and tension loads and lateral forces.
The connections of the roof to the URM walls in both the longitudinal and transverse directions do not have sufficient capacity to transfer the roof diaphragm forces into the supporting URM walls. In addition, the roof diaphragm appears to have a horizontal separation adjacent to the wall at line b (interior longitudinal wall). Additional steel diagonal members and connections/attachments are required.
The summary of results (demand/capacity ratios) for in-plane shear forces in the walls is presented in Table 2. The average elastic capacity for each wall was based upon the results presented in Table 1 "Elastic Capacity". The demand for each wall was obtained from a three-dimensional computer analysis as described above and presented as in-plane shear stress iso-contour plots, see Figure 8. Note that Figure 8 shows in-plane shear stress iso-iso-contour plot for Wall B, similar plots were generated for all lateral force resisting shear walls. The results show that the wall on grid line 7 and the lower portion of the wall on grid line 8 require pointing as previously discussed.
The ability of the URM walls to withstand out-of-plane forces was also considered. The capacity for each wall is generated in Table 3 based upon the theory and equations developed in Reference 2. Capacity is expressed as a coefficient, Cp which is the wall out-of-plane capacity divided by wall weight. Cp values range from about 0.4 to 12 in Table 3. The demand for each wall is obtained from the theory and equations developed in Reference 8 and essentially represents the dynamic behavior of a singly supported wall spanning between the roof and floor. For all walls, the demand is estimated to be 0.63 times the wall weight. The results show that solid walls are adequate for out-of-plane forces (except for the wall on grid line 10 which has an exceptionally large height to thickness ratio). However, it is recommended that "strongback" members be installed adjacent to large openings to assure stability.
Demand/capacity ratios for other structural members and connections were also computed.
The capacity of the various elements is generated essentially by manual calculations while the demand is essentially determined from the three-dimensional computer analysis. The results show that the roof diagonal bracing members must be strengthened. This will also allow these members to act in both tension and compression and better distribute the lateral forces.
143
TABLE 2. SUMMARY OF RESULTS [D/C RATIO] WALLA IN-PLANE SHEAR
(1) See Figure 11, Sample/Example In-Plane Shear Stress Iso-Contour (2) Pa = 6.89 (psi)
(3) See Table 1
P \250I07IO\URM I XLS
483E+0I <JO]NT 299> MAX IS .o3IE*02 <JOINT 323>
d\dgr SHELL OUTPUT FI2 LOAD 2
*».
A7
52
39 26 13 0
SAP90
Figure 8: In Plane Shear Stress Iso Contour
Structural Strengthening/ConclusionsThe deficiencies found from the seismic evaluation of the Emergency Generator Station lateral force-resisting system can be corrected by providing a supplemental lateral force-resisting system, and through strengthening of the existing system. The strengthening concept basically includes providing new steel diagonal vertical bracing members along the exterior wall at building line A; additional steel connections/ attachments at the roof to the supporting URM walls, vertical steel "strongbacks" at wall lines B, b and 10, stiffening of horizontal roof bracing and pointing of two interior transverse walls.
The five specific problem areas in the existing lateral force-resisting system of the Emergency Generator Station/Building, along with strengthening measures are described in the following paragraphs.
1. Strengthening of roof diagonals (i.e. add angle shape to make box shape element from existing single angle). This strengthening is required for all horizontal diagonal roof elements. Details are also shown to provide shear transfer between the apparent horizontal discontinuity in the roof diaphragm parallel to building line b, see Figure 9.
2. Connections of the roof diaphragm to the supporting vertical URM walls, see Figure 10.
3. Additional steel diagonal braces and connections to existing steel columns. Note
that there are two sets of diagonal braces; one for the vertical lateral force-resisting
system which extends from the roof to the first floor in three bays and the other set of braces is for a "drag strut" to connect the mezzanine(s) to the vertical lateral force-resisting systems located in three different bays, see Figure 11.145
TABLE 3. SUMMARY OF RESULTS [CP RATIO]: CAPACITY WALLS FOR OUT OF
PLANE FORCES — REF. 2
Wall
4. Additional "strongback" members are also recommended to be installed on walls along lines B and b due to the number of large openings and along the wall at line 10 due to its excessive h/t ratio, see Figures 12 and 13.
5. Pointing of the URM wall along grid line 7 and at the lower portion of the URM wall along grid line 8, see Figure 7.
Implementation of these recommendations will provide the increased lateral force-resisting capacity required by Reference 1 for the Emergency Generator Station to withstand the iRLE such that the emergency generators remain operational.
m e± ; & i
\XI\xd
\/i\
I I
1^3000 L3OOO j>3OOO LJOOOy 6000 v 6000 ^ 6000 „ 6000
lu. g
43
{,3000 ^3000^600^400 6000
•*- 6000
-|-S4000
T
Figure 9: Level +10.24, Roof
147
DETAIL S1.2.
SELF DRILLING SCREWS M10
BENT PLATE t=8mm L,xL,x200 AT 1m ON CENTER
1|
NEW EPOXY ANCHORS FOR UNREINFORCED MASONRY 2xM20 HILTI (KW1K I!) BOLTS
EXIST. MASONRY WALL
1-1
ROOF PANEL
EXIST. STEEL BEAM
3 z.aez
BENT PLATE t=8mm Ljx250x100
AT 1m ON1 CENTER
2-2
},60|60].60^
SOL 150 250
ROOF PANEL
3 sides
* CONTRACTOR TO MEASURE AT FIELD
+
250
>
0
Figure 10: Detail SI.2, At Roof
STEEL BRACING 'B' STEEL BRACING *A'
SB
\
zooo^ ^3000j,30QOj.3000^.3000 „
I I
^3000 13000 ,,3000 |
6000 6000 £000 6000 6000 6000 6000 6000 6000
54000
Figure 11: Exterior Wall Elevation At Line "A", Looking South
TYPICAL DETAILS F0«
MASONRY WALLS' UPGRADE SE£ HO. £-13
I
~
\
X
20011. J,3OOO 1,3000 i,3000 1,3000 L L, 6000 y 6000 $OOO
L3000L30OO 1,3000 I.30OO u J,3OOO U30OO L,30OO U600j,|,«00 6000 y 6000 b 6OOO L 6000 L 6000 I, 6000 I,
-if-
-4-Figure 12: Exterior Wall Elevation At Line "B", Looking South
149
U f:SO
E
ROOF PANEL
MASONRY WALL
MASONRY WALL
•VERTICAL ELEMENT COMBINED SECTION 2xU1B
mini 50
1-1
SELF DRILLING SCREWS M10
CONCRETE SLAB
U I.-2O
A--CONCRETE SLAB
ROOF PANEL BENT PLATE t=8
L,xL,x200 EPOXY ANCHORS FOR URM
2xM20 HILTI
AT t:2O
2-2 3-3
50
r
HEAVY DUTY ANCHORS 2xM20 HILTI
PLATE t-8mm 100x100x6
EPOXY ANCHORS FOR URM
2xM20 HILTI
Figure 13: Typical Details for Masonry Walls' Upgrade
ACKNOWLEDGEMENTS
The work presented in this paper is part of an ongoing seismic evaluation of the EBO nuclear facility located in Bohunice, Slovakia. The support of EBO is greatly appreciated. The in-place shear tests were performed by Professor Dr. Baiza, Department of Material Engineering, University of Bratislava and technical staff from Siemens. Assistance from the University and Siemens is gratefully acknowledged.
REFERENCES
1. "Seismic Qualifications and Design Procedure - Part A: Civil Structures," for the EBO V-l Project, Konsortium REKON, Siemens-Vuje.
2. Abrams, Daniel P., Richard Angel and Joseph Uzarski, (1996), "Out-of-Plane Strength of Unreinforced Masonry Infill Panels," Earthquake Spectra, Vol. 12, No. 4, November.
3. Manzoui, Leyman, Michael Schuller, Benson Shing and Bernard Amadei, (1996), "Repair and Retrofit of Unreinforced Masonry Structures," Earthquake Spectra, Vol. 12, No. 4, November.
4. International Council of Building Officials, "1994 Uniform Building Code," Whittier, California.
5. International Council of Building Officials, 1994 Uniform Code for Building Conservation,
"Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings, "
Appendix, Chapter 1, Whittier, California.
6. International Council of Building Officials, 1994 Uniform Building Code Standard 21-6,
"In-Place Masonry Shear Test," Whittier, California.
7. General Structural Analysis Program (SAP 90), Computers and Structures, Inc., 1918 University Avenue, Berkeley, California 94704.
8. Shipp, John G. "Structural Designs of Wood Structures" Two Volumes. Professional Engineering Development Publications, Inc. 5912 Bolsa Avenue, Huntingdon Beach, CA 92649.
9. Basic Engineering Report, "Fire Protection in Main Buildings of Bohunice VI, Units 1 & 2 (Design Review)" - NDBS/95/028, R. Molinaui, Siemen KWU-NDA5, April 1995.
15.1
SEISMIC UPGRADING OF THE SPENT FUEL STORAGE XA01