Structural Damage of a 5-Storey Building: Differential Settlement Due to Construction of an Adjacent Building or Because of Construction Defects?

The paper presents a case history of a 5-storey RC building in Athens (Greece), seriously damaged due to differential settlement. Built in 1968, the damaged structure is founded on spread footings, lying on very soft clayey soil. For more than 30 years, no damage had been observed. In 1999, construction of an adjacent 5-storey RC building begun, and shear cracks started appearing. Inclined at 45o, the cracks implied damage due to differential settlement. The owners of the damaged building filed a law suit, claiming that the damage was due to additional loading by the under-construction adjacent building. Measurements conducted in 2011, revealed that the differential settlements were of the order of 5 cm. However, the present study also revealed that the damaged building had a number of construction defects, with the most important one being the absence of tie beams. In order to assess the relative importance of the two factors (construction of the adjacent structure vs. construction defects), numerical analyses were conducted modeling both buildings in detail, and taking account of the construction sequence. It is shown that due to the defective foundation of the damaged building, almost 70% (3.5 cm) of the differential settlement had already taken place before construction of the adjacent building. The latter, founded on a slab foundation, settled by about 3 cm, increasing the differential settlement of the damaged building by roughly 1.5 cm. No damage would have taken place, had the building been constructed according to code specifications

A theoretical study and computer search for binary sequences having specific auto-correlation functions

Binary sequences find increasing use in electrical engineering applications of ranging, time measurement and communications. A property of interest in these applications is the autocorrelation function of the binary sequence or pair of sequences. Of the 2 possible sequences of length n, only a few have usable autocorrelation functions. There is, to date, no procedure known which will provide the sequence having a specific autocorrelation function, except for very particular cases . In this report, known properties of complementary sequences are reviewed. Almost complementary sequences are defined and the procedure to obtain them is outlined. A formula is derived for the number of different autocorrelation functions of the 2 possible sequences of length n bits. A computer search is implemented with the objective of discovering sequences with desirable autocorrelation functions.http://archive.org/details/theoreticalstudy00anasLieutenant, Hellenic NavyApproved for public release; distribution is unlimited

Ανάπτυξη και επικύρωση μεθόδων για τον προσδιορισμό φαρμακούχων ενώσεων σε ιχθυοτροφές, με χρήση τεχνικών υγροχρωματογραφίας με ανιχνευτές ορατού υπεριώδους (UV-VIS), φωτοδιόδων (DAD) και διαδοχικής φασματομετρίας μαζών (MS/MS)

Η παρούσα εργασία έχει ως σκοπό την ανάπτυξη και επικύρωση αναλυτικών μεθόδων, για τον προσδιορισμό φαρμακούχων ενώσεων σε ιχθυοτροφές. Συγκεκριμένα αναφέρεται στον προσδιορισμό των ενώσεων : Υδροχλωρική Οξυτετρακυκλίνη, Σουλφαδιαζίνη και Τριμεθοπρίμη. Στόχος είναι ο προσδιορισμός περιεκτικότητας των πρώτων υλών που χρησιμοποιούνται για τη παραγωγή των ιχθυοτροφών, του τελικού προϊόντος καθώς και της γραμμής καθαρισμού. Για την ανάπτυξη των παραπάνω μεθόδων χρησιμοποιήθηκε η τεχνική υγροχρωματογραφίας υψηλής απόδοσης με ανιχνευτή ορατού / υπεριώδους (HPLC UV/VIS), και ανιχνευτή φωτοδιόδων (DAD). Για τον προσδιορισμό της τριμεθοπρίμης στις γραμμές καθαρισμού, λόγο των πολύ χαμηλών συγκεντρώσεων χρησιμοποιήθηκε η τεχνική υγροχρωματογραφίας συζευγμένης με φασματομετρία μαζών σε σειρά (LC MS/MS). Το πειραματικό μέρος χωρίζεται σε δύο άξονες. Αρχικά στην ανάπτυξη και βελτιστοποίηση των παραπάνω μεθόδων και έπειτα στην επικύρωσή τους. Συμπερασματικά, για την υδροχλωρική οξυτετρακυκλίνη επικυρώθηκε μια μέθοδος που επιτρέπει τον προσδιορισμό της στην πρώτη ύλη, το τελικό προϊόν καθώς και στην γραμμή καθαρισμού. Αντίστοιχα και για τις άλλες δύο ενώσεις επικυρώθηκε μια κοινή μέθοδος προσδιορισμού της πρώτης ύλης και του τελικού προϊόντος. Όσο αφορά την γραμμή καθαρισμού για την σουλφαδιαζίνη χρησιμοποιήθηκε η παραπάνω μέθοδος, ενώ για την τριμεθοπρίμη επικυρώθηκε άλλη μέθοδος στο (LC MS/MS).In this thesis, we study the development and validation of analytical methods, for the determination of medicated compounds in fish feeds. Specifically, it relates to the determination of the compounds: Oxytetracycline Hydrochloride, Sulphadiazine and Trimethoprim. The aim is to determine the content of raw materials used for the production of fish feed, the final product and the cleaning line. For the development of the above methods, the high-performance liquid chromatography technique was used with a visible / ultraviolet detector (HPLC UV / VIS) and diode array detector (DAD). To determine the trimethoprim in the purification lines, the liquid chromatography coupled with mass spectrometry (LC MS / MS) was used, because of the very low concentrations. The experimental part is divided into two axes. Initially develop and optimize the above methods and then validate them. As a result, for oxytetracycline hydrochloride, a method that allows its determination in the raw material, the final product as well as the purification line has been validated. Similarly, for the other two compounds, a common method for determining the raw material and the final product was validated. As regards the purification line for sulfadiazine, the above method was used, while for the trimethoprim another method was validated in LC MS / MS

Design of Bridges Against Seismic Faulting : Methodology and Applications

This paper presents a methodology for design of bridge–foundation systems against seismic faulting. The problem is decoupled in two steps. Step 1 deals with the response of a single bridge pier and its foundation subjected to faulting–induced deformation ; Step 2 deals with the detailed model of the superstructure, which is subjected to differential displacements computed in Step 1. We analyze typical viaduct and underpass bridges, founded on piles or caisson foundations. Piled foundations are found to be vulnerable to faulting– induced deformation. While end–bearing piles cannot really sustain any appreciable bedrock offset, floating piles may perform better, especially if combined with hinged pile–to–cap connections. Statically–determinate superstructures are shown to be less sensitive to faulting– induced differential displacements and rotations. Finally, an application of the method is shown for a major bridge, demonstrating the feasibility of design against seismic faulting

Experimental Soil - Foundation - Bridge Pier Interaction : Towards a Reversal of Capacity Design

This paper presents a new seismic design philosophy, which under-designs the foundation to act as a “fuse” in case of strong seismic shaking. A simplified bridge pier is used to illustrate the advantages and disadvantages of this new philosophy compared to conventional capacity design. For this purpose, two alternatives are compared : one with an over-designed foundation, in accordance with conventional capacity design (so that the plastic “hinge” develops in the superstructure), and one with under-designed foundation. The performance of the two alternatives is investigated through shaking table testing of reduced scale models, using real accelerograms and artificial sinusoidal motions. It is shown that the performance of both alternatives is acceptable for moderate seismic shaking. For larger intensity ground motions, that clearly exceed the design limits, the performance of the new design concept is advantageous, not only avoiding collapse but hardly suffering any inelastic structural deformation. The price to pay is mainly the increase of seismic settlements, and in some cases of permanent foundation rotation