Testing of small scale structural models (engl.)

(as Part of NHRE: “Experimental structural evaluation and rehabilitation”)

(I) Motivation

Students will be familiar with testing methods and simulation requirements to provide structure related parameters and relationships in support of analytical studies, to undertake general design consideration and to compare the outcome of field surveys and of simple model testing with general design consideration.

Students should be able to decide upon appropriate test configuration for particular problems related to failure cases or ongoing projects, and to use the infrastructure for further graduation (Master Thesis).

 

The Participants have the opportunity

  • to check and evaluate the resistance of existing simple masonry buildings (Figure 1),
  • to provide input data for analytical investigation,
  • to discuss the benefits and limits of small scale models as well as the outcome of their testing,
  • to check and evaluate the design and construction of high-rise office buildings (Figure 2),
  • to analyze uncommon, innovative and creative solutions for different levels of design earthquakes, 

Students have to be trained in the selection of ground motion records to come up with realistic (data-proven) input excitation for different performance levels.

The reference buildings have to be derived from the home countries or refer to target seismic areas studied within EDAC projects.

(II) Specification of Tasks

Task 1 - Small scale modeling and testing of masonry buildings

Figure 1: Example from the test series performed by A. Sieberg (1935-1940): 1-directional horizontal impact on a small scale masonry wall model (without “mortar-like” material between the stone units)

Task 1.1

Decision upon a typical masonry type built from manufactured stone units (brick, concrete block)


Note:

  • Building has to be is taken from the buildings stock shaken by the Albstadt, September 1978, EQ (Schwarz et al., 2008; 2010).
  • Alternatively, building can be selected on the basis of EERI-WHE reports related to national relevant masonry building types or other unreinforced masonry buildings being faced to strong ground motion and sustaining a reproducible damage by the earthquake shaking.

 

Task 1.2

  • Elaboration of the structural layout and main structural elements;
  • Digitization of the structural layout using archive data (in fotocopy format),
  • Preparation of input files for numerical simulation in Form of AutoCAD-File.


Task 1.3

  • Evaluation of the structural layout with respects to regularity criteria (symmetry, eccentricity within the story and between); 
  • Check of opening structure (size of the openings, distance of the openings to wall intersections etc.) according to Eurocode  EC8 requirements;
  • Calculation of percentage of resisting shear wall area in both directions and its comparison with the Eurocode requirements;
  • Damage prognosis (critical zones, damage grade assuming the parameters of the reference EQ). 


    Task 1.4

    • Transformation of the building into a small scale model (see Figure 1);
    • Decision upon the scale (depending on the size of base plate);
    • Creation of a simplified model for the main structural system.


    Task 1.5

    • Analysis of the building using 3MURI software
    • Elaboration of capacity curves and different damage grades
    • Comparison of the already predicted damages (task 1.3) with the results from 3MURI software


    Task 1.6 [presentation by the lecturer within project workshop]

    • Numerical simulation; Identification of damage and failure modes;
    • Reconstruction of the observed damage;
    • Identification of typical damage pattern (critical zones, crack distribution)
    • Comparison of empirical, analytical and instrumental results.
    • Discussion  on the level of ground motion records (including subsoil characteristics) from the damaging earthquake(s) which might have affected building/or buildings of the selected masonry wall type


    Task 1.7 [optional within a Special Project]

    • Preparation of the model for shaking test
    • Decision on ground motion components
    • Experimental testing
    • Modification of structural layout (following modern solutions with a minimum percentage of shear   wall area)
    • Elaboration of fragility functions using a sample of different structural layouts.


    Deliverables (Results)

    • Drawings/Digitization of the structural layout and the main structural system
    • Evaluation of structural layout
    • Scheme for Small Scale Model of the selected building;
    • Prognosis of probable failure (critical zones, crack distribution) in case of strong ground motion.
    • 3MURI analysis results


    References:

    Schwarz, J., Beinersdorf, S., Swain, Th. M., Langhammer, T., Leipold, M., Kaufmann, Ch., Wenk, Th. (2008):Realistic vulnerability and displacement functions for masonry structures derived from damaging earthquakes in Central Europe. In Proceedings 14h World Conference on Earthquake Engineering, 12-17 October 2008, Abstract ID: 05-04-0060, Beijing, China.

    Schwarz, J., Beinersdorf, S., Langhammer, T., Leipold, M., Kaufmann, Ch. (2010):Vulnerability functions for masonry structures derived from recent earthquakes in Germany. Proceedings of 14th European Conference on Earthquake Engineering, August 30 - September 03, 2010, Ohrid, Macedonia. (Abstract ID: 606)

    Sieberg, A. (1937):Beiträge zur erdbebenkundlichen Bautechnik und Bodenmechanik. I. Qualitative Versuche über Erdbebenstöße und ihre zerstörende Wirkung auf Ziegelmauerwerk. II. Gebäudeschäden und ihre geologische Bedingtheit beim Oberschwäbischen Erdbeben vom 27. Juni 1935. Veröffentlichungen der Reichsanstalt für Erdbebenforschung, Heft 29, 78 S. Berlin 1937.

    Sieberg, A. (1941):Neuere Untersuchungen der Reichsanstalt für Erdbebenforschung über bautechnische Erdbeben-sicherung.Zeitschr. für Geophysik 17 (1941) 3/4, 84-102 Druck und Verlag von Friedr. Vieweg & Sohn, Braunschweig 

    Web:World Housing Encyclpedia: www.world-housing.net

    Task 2 - Small scale modeling and testing of high-rise buildings

    Figure 2: Dynamic model of the 16-storey steel frame Alexander Building prepared by John A. Blume and tested as Graduate Student in 1934 [Stanford University; Earthquake Engineering Research Center; Foto: EDAC, 2011).

    Taking Reference to EERI Annual Undergraduate Seismic Design Competition students have to check the resistance of the designed and constructed models of a multi-story commercial office building. On the basis of Video, the response of selected frame structures (provided by civil engineering undergraduate students from different universities) under horizontal earthquake excitations has to be re-interpreted.

    It should be taken into account that each model is subjected to three levels of severe ground motion (corresponding to the following return periods.

    GM1                       TR = 50 years
    GM2                       TR = 150 years
    GM3                       TR = 300 years

    Models are constructed from balsa wood. (The time histories and response spectrums are available online in the competition website.)
     

    Task 2.1 Presentation of examples of EERI Annual Undergraduate Seismic Design Competition

    Points of discussion:

    • Identification of the load-bearing system for vertical and horizontal action
    • Elaboration of the structural layout and the main structural system and principles suitable for resisting strong horizontal shaking
    • Efficiency of the system and critical zones;
    • Interpretation of the response (Identification of typical damage pattern considering failed connections and elements; Qualification of failure type and the effect of local failure to the total response).  

    Task 2.2
    Comparison between prognosis (drifts) for the three test EQs and observed response (under shaking)

    Task 2.3 [Optional within a Special Project]

    • Preparation of an ETABS model for simulation
    • Comparison between prognosis and observed response
    • Evaluation of the scoring method and basic assumptions for loss prediction.


    Presentation of results:
    According to time schedule

    Deliverables (Results)

    • Short Note including the screenshot/drawing of the structural layout and the main structural system
    • Capacity curve (predicted by competition team) and predicted response (acc. to task 2.2)

    Web:
    Rules for the competition: slc.eeri.org/SDC2014_2015.htm


     

    Report:

    (Including results from tasks 1 and 2)
    Submission date: According to time schedule