Module on the Assessment of the Structural Condition

Bucharest October 5-7, 2010

1st MEMSCON Event07/10/10, Bucharest DBA

Condition Assessment Based on Strain Measurements (Long-term Behavior)

DBA1st MEMSCON Event - 07 October 10, Bucharest

Direct Evaluation of Internal Forces from Measurements Data

 

Required number of strain sensors :

Column Cross-section : 3

Beam Cross-section : 2

Columns : 2 Cross-sections : 2x3= 6

Beams : 3 Cross-sections : 3x2= 6

Example : 5 storey building

25 columns and 40 beams per storey

 

Required number of strain sensors :

N = 5 ( 25x6+40x6 ) = 5x390 = 1950

Condition Assessment Based on Strain Measurements (Long-term Behavior)

DBA1st MEMSCON Event - 07 October 10, Bucharest

Indirect Evaluation of Internal Forces by Computer Aided Analysis Main Long-term Effects :

Shrinkage and Creep of Concrete

Differential Foundation Settlements

From measurement data, the variations of the reaction forces on the foundation are evaluated

The internal forces of the totality of the elements are calculated by a non linear analysis computer program

Required number of strain sensors:

Base column cross-section over the foundation : 3

Concrete specimen for shrinkage measurement : 2

Concrete specimen for creep measurement : 2

For the above example: N = 25x3+2+2 = 79

Condition Assessment Based on Strain Measurements (Long-term Behavior)

DBA1st MEMSCON Event - 07 October 10, Bucharest

2. Long Term Behavior

2.2 Local ConditionTable 3: Actual and Ultimate Internal Forces – Safety Factors

2.3 Global ConditionTable 4: Differential Settlemennts

DBA1st MEMSCON Event07/10/10, Bucharest

Column Internal Forces – Actual Internal Forces - Ultimate Safetyc60/40 N Mx My NR MxR MyR Factor52 -778.67 208.69 -13.60 -2658.15 712.41 -46.41 3.4153 -804.09 20.41 -131.89 -6761.24 171.58 -1108.98 8.4154 -1280.71 -261.52 34.81 -3439.06 -702.26 93.47 2.6955 -1078.04 -10.31 152.93 -2107.08 -20.16 298.91 1.9556 -778.67 208.69 -13.60 -2658.15 712.41 -46.41 3.4157 -1039.17 20.09 141.92 -1161.03 22.44 158.57 1.12

Column Ng NQ,n Nn ΔNn Δδ,n ΔδG,n ΔδQ,n

52 -584.00 -199.41 -778.67 -9.42 -0.0041 -0.0031 -0.0010

53 -619.15 -176.40 -804.09 11.45 -0.0032 -0.0024 -0.0007

54 -1011.76 -245.81 -1280.71 51.98 -0.0087 -0.0066 -0.0019

55 -840.87 -211.76 -1078.04 29.56 -0.0071 -0.0054 -0.0015

56 -568.43 -197.16 -778.67 -29.93 -0.0039 -0.0030 -0.0009

57 -748.20 -274.38 -1039.17 -53.64 -0.0036 -0.0027 -0.0008

2. Long Term Behavior2.3 Global Condition

Non-linear structural analysis by SAP2000

γG(DL) +γQ(LL)+ γG(ΔδG)+γQψ1(ΔδQ)+γG(S)

From the analysis results the capacity of the structural members:

Table 5: Internal Forces

DBA1st MEMSCON Event07/10/10, Bucharest

Frame Station OutputCase CaseType P V2 V3 T M2 M3 PMMRatioText m Text Text KN KN KN KN-m KN-m KN-m Unitless

52 0COMB1 Combination -189.7 -3.15 -5.17 0 -5.4 -2.9 0.056552 3.5COMB1 Combination -168.7 -3.15 -5.17 0 12.71 8.11 0.069253 0COMB1 Combination -189.7 -3.15 5.17 0 5.4 -2.9 0.056553 3.5COMB1 Combination -168.7 -3.15 5.17 0 -12.71 8.11 0.069254 0COMB1 Combination -298.2 0.26 -7.02 0 -6.27 0.11 0.088354 3.5COMB1 Combination -277.2 0.26 -7.02 0 18.32 -0.8 0.101755 0COMB1 Combination -298.2 0.26 7.02 0 6.27 0.11 0.088355 3.5COMB1 Combination -277.2 0.26 7.02 0 -18.32 -0.8 0.101756 0COMB1 Combination -184.9 2.89 4.8 0 5.25 2.91 0.055156 3.5COMB1 Combination -163.9 2.89 4.8 0 -11.55 -7.2 0.06457 0COMB1 Combination -184.9 2.89 -4.8 0 -5.25 2.91 0.055157 3.5COMB1 Combination -163.9 2.89 -4.8 0 11.55 -7.2 0.064

3. Seismic Behaviour

DBA1st MEMSCON Event07/10/10, Bucharest

δx1,δy1,δx2,δy2 : Horizontal displacements at A1,A2 as functions of time δ = δ(t) , resulting after double integration of the acceleration α = d(t)

3. Seismic Behaviour3.1 Seismic Displacements

Velocities:

Displacements: Table 6: Accelerations and displacements at the positions of the two

accelerometers in the storey m.

DBA1st MEMSCON Event07/10/10, Bucharest

Storey 1n tn (x10^-3s) a(11x) δ(11x) a(11y) δ(11y) a(12x) δ(12x) a(12y) δ(12y)1 0.0 -4.54274552 -7.098E-06 -5.615 -8.774E-06 4.937 7.715E-06 -2.104 -3.288E-062 2.5 2.91755656 -2.383E-05 -1.558 -3.753E-05 -1.464 2.857E-05 6.157 -3.533E-063 5.0 4.37274565 -3.172E-05 -0.045 -8.000E-05 -4.283 4.588E-05 4.441 1.911E-054 7.5 2.8562432 -1.691E-05 -6.080 -1.346E-04 0.962 4.901E-05 4.739 7.266E-055 10.0 -0.89236307 1.225E-05 5.440 -1.997E-04 -4.446 4.152E-05 5.735 1.569E-046 12.5 6.72968637 5.361E-05 4.211 -2.507E-04 -3.430 1.627E-05 -2.050 2.633E-047 15.0 -0.7127606 1.135E-04 1.611 -2.776E-04 -4.407 -3.353E-05 -3.211 3.672E-048 17.5 -6.23239902 1.719E-04 1.411 -2.906E-04 -0.612 -1.034E-04 -4.097 4.515E-049 20.0 0.96207225 2.113E-04 -4.717 -3.041E-04 -2.564 -1.861E-04 0.973 5.195E-0410 22.5 -0.55062712 2.430E-04 -6.500 -3.403E-04 -0.970 -2.793E-04 0.672 5.851E-0411 25.0 -4.61449301 2.673E-04 -0.489 -4.050E-04 1.552 -3.771E-04 2.982 6.591E-0412 27.5 3.75002087 2.822E-04 -6.769 -4.919E-04 3.733 -4.657E-04 -4.635 7.361E-0413 30.0 1.57766114 3.041E-04 -5.797 -6.097E-04 -0.152 -5.405E-04 4.147 8.099E-0414 32.5 -2.96115475 3.321E-04 -1.899 -7.593E-04 -0.552 -6.107E-04 -1.511 8.869E-0415 35.0 3.00919965 3.581E-04 0.661 -9.228E-04 3.151 -6.780E-04 2.128 9.691E-04

𝐯𝐧 = 𝐯𝐧−𝟏 + 𝟏𝟐ሺ𝐚𝐧−𝟏 + 𝐚𝐧ሻሺ𝐭𝐧− 𝐭𝐧−𝟏ሻ

𝛅𝐧 = 𝛅𝐧−𝟏 + 𝟏𝟐ሺ𝐯𝐧−𝟏 + 𝐯𝐧ሻሺ𝐭𝐧− 𝐭𝐧−𝟏ሻ

3. Seismic Behaviour3.3. Local Condition

DBA1st MEMSCON Event07/10/10, Bucharest

Total Plastic Rotation

Resultant Bending Moments

Damage Index

Table 10. Damage Index DMember End point M

121212

4

1

2

3

3. Seismic Behaviour3.4. Global Condition

DBA1st MEMSCON Event07/10/10, Bucharest

Total Failure Condition

Formation of Plastic Hinge Storey Mechanism

3. Seismic Behaviour3.4. Global Condition

DBA1st MEMSCON Event07/10/10, Bucharest

0.20 Plastic Hinge

IF

nm: The number of columns in the storey

2nm: The required number of hinges for instability

nhm: The number of hinges develeved in storey , the index

of instability of the storey is

Index of the Global Instability of the Building

Table 11. Index of Global Instability

1234.

Storey Number of Columns

Number of Plastic Hinges

Instability Index