29.05 – 31. 05. 2013 Comparison Between Three Base Isolation Systems-Shake Table Test Studies ID 516 DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L., University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Abstract: This paper deals with three base isolation techniques for seismic protection of two different types of structures: liquid storage tanks and buildings. The effectiveness of these techniques was investigated experimentally on reduced scale models in laboratory conditions at the Dynamic Testing Laboratory of the Institute of Earthquake Engineering and Engineering Seismology, Skopje. The first technique was related to base isolation by standard rubber bearings. Such type of isolation was applied on the model of St. Nikita church built to the scale of 1/2.75. The second technique was related to base isolation by high strength rubber bearings. This type of bearings was applied on a liquid storage tank model built to the scale of 1/3. The third technique was related to base isolation by ALSC floating-sliding system. This technique was applied on a liquid storage tank model as well as on the St. Nicholas church model built to the scale of 1/3. First, a comparison was made between the church models (standard rubber and ALSC base-isolation system) and then between the reservoir models (high strength rubber and ALSC base-isolation system) The comparative diagrams of the model responses showed superior behavior of the ALSC floating-sliding system in both cases. DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Case study No. 1: SHAKE-TABLE TEST OF 1/2.75 SCALED MODEL of st. nikita church BASE-ISOLATED BY laminated rubber bearings St. Nikita church near Skopje considered as a prototype structure Model of the St. Nikita church in scale 1/ 2.75 with laminated rubber bearings on the shake table at IZIIS DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Test results : St. Nikita church model Figure 2.2.1. Response of the St. Nikita church model Figure 2.2.2. Response of the St. Nikita church model base-isolated by rubber bearings fixed to the base DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Model of the St. Nikita church in scale 1/ 2.75 with laminated rubber bearings DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies CASE STUDY NO 2: SHAKE-TABLE TEST OF 1/3.5 SCALED MODEL OF SENT NICHOLAS CHURCH, BASE ISOLATED BY FLOATING-SLIDING SYSTEM “ALSC” St. Nicholas church near Psacha considered as a prototype structure Model of St. Nicholas church in scale 1/3.5, base-isolated by ALSC floating-sliding system DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Shendova V., Krstevska L., Gavrilovic P. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies The concept of ALSC floating-sliding base isolation system Fr=N (1) a) Ordinary sliding: N=G, L=0 (2) b) ALSC sliding: N= G-L, GL  N N  0 L=pS ; (3) (for L=G ; N becomes 0 and Fr=0 i.e. floating state) Fr = friction force;  = friction coefficient at the contact surface; N = active compressive force; L = uplifting force produced by the liquid; G = weight of the principal structure; p=liquid pressure; S= contact surface between the sliding and the fixed plate DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Test results : St. Nicholas church model Figure 3.3.1. Response of the St. Nicholas church model Figure 3.3.2. Response of the St. Nicholas base isolated by floating-sliding system ALSC. church model fixed to the base. DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Shendova V., Krstevska L., Gavrilovic P. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Fixed base model of Byzantine Church system Montenegro-Petrovac Input: 0.5g DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Base-isolated model of Byzantine Church by ALSC floating-sliding system Harmonic 5Hz input:0.8g DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies CASE STUDY NO 3 – BASE-ISOLATED RESERVOIR WITH ALSC FLOATING-SLIDING SYSTEM DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Figure 4.3. Response of reservoir isolated by ALSC Figure 4.4. Comparative presentation of reservoir system under harmonic excitation isolated by ALSC system and fixed to the base DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Base-isolated reservoir by ALSC floating-sliding system Harmonic: 3.5Hz Input: 1.2g DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Fixed base reservoir without base-isolation Harmonic-3 Hz Input: 0.7g DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies CASE STUDY NO 4 – BASE-ISOLATED RESERVOIR WITH HIGH STRENGTH RUBBER BEARINGS Fig.5.1. Model of a reservoir base-isolated with high strength rubber bearings. DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Fig.5.4. Comparative presentation of acceleration response of reservoir tsolted with soft and hard rubber- Harmonic excitation test (left) and Earthquake excitation test (right) DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Model of a reservoir base-isolated with high strength rubber bearings DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Model of a reservoir base-isolated with high strength rubber bearings DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies COMPARISON BETWEEN TWO BASE ISOLATION SYSTEMS: ALSC AND RUBBER BEARINGS IN CASE OF CHURCH MODELS Figure 7.1. Response of the St. Nikita church mode Figure 7.2. Response of the St. Nicholas church base-isolated with rubber bearings. base-isolated with floating-sliding system ALSC. DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies Comparison between two base isolation systems: ALSC and Rubber bearings in case of reservoirs base isol- hatedard rubber base isolated- ALSC Input Input base isolated - soft rubber base isolated- ALSC . Comparison between hard rubber, soft rubber and ALSC base-isolation system DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

Comparison Between Three Base Isolation Systems -Shake Table Test Studies 5. CONCLUSIONS The presented techniques of base isolation showed different effectiveness in reduction of seismic energy transmission from the foundation to the structure in all 4 case studies. Based on the performed experimental investigations, the following conclusions can be drawn: The base isolation with laminated rubber isolators applied to the model of the St. Nikita church shows that it can effectively protect the historical monuments from severe damage up to limited level of input acceleration (0.5g for the model); The ALSC floating-sliding base isolation system applied to the model of the St. Nicholas Church shows very effective reduction of the response during dynamic excitation. The effectiveness of this isolation system is much better than that of the laminated rubber isolators, preventing damage to the model up to 1.5 g ( the limit capacity of the IZIIS’ shake table); The base isolation with high strength rubber isolators applied to the reservoir model shows that base isolators with hard rubber do not have any isolation effect, while soft rubber has limited effectiveness (for the frequency of excitation higher than 3.0 Hz.) In the lower frequency range, it produces amplification of the input motion. It can be concluded that this base-isolation is very sensitive to design conditions; The base isolation with ALSC system applied to the model of reservoir shows very effective reduction of the response during dynamic excitation. The effectiveness of this isolation system is much better than that of the high strength rubber system, preventing damage to the model and providing almost constant and effective base-isolation within the broad frequency and amplitude range of excitation(frequency range 0-25 Hz, amplitude response less than 0.25g for input up to 1.5g) . DEPARTMENT FOR BUILDING STRUCTURES AND MATERIALS, DESIGN, ANALYSIS AND TESTING Tashkov L., Krstevska L. University Ss. Cyril and Methodius in Skopje Institute of Earthquake Engineering and Engineering Seismology (UKIM-IZIIS) - Skopje

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