M.A. StruTec Engineers

12/11/2025

Η άποψη μου για τους σημερινούς σεισμούς.
Τα Richter είναι αυτό που νιώθουμε ως άνθρωποι. Αρκετές φορές πιο λίγα Richter προκαλούν μεγαλύτερη επιτάχυνση. Σημαντικός παράγοντας είναι η επιτάχυνση, το εστιακό βάθος, το είδος του σεισμικού κύμματος κτλ.
Το πρωί είπα σε συναδέλφους Πολιτικούς Μηχανικούς ότι με μετασεισμό 4.7 (earthquake M4.7 CYPRUS REGION, 2025-11-12 09:41:51 UTC https://m.emsc.eu/?id=1897626) να περιμένετε δυνατό αν οχι πιο δυνατό σεισμό και έτσι και έγινε με τον σεισμό των 5.3 Richter με 9.2 km εστιακό βάθος.
(earthquake M5.3 CYPRUS REGION, 2025-11-12 14:23:31 UTC https://m.emsc.eu/?id=1897742)

Ως Πολιτικοί Μηχανικοί υπολογίζουμε την εδαφική σεισμική επιτάχυνση και όχι τα Richter, για να διαστασιολογίσουμε τις κολωνες, τις δοκους, γενικώς τα κτήρια, τι οπλισμός, τι διατομές απαιτούνται, κτλ.

Μετά τον μεγάλο σεισμό του 1996 6.8 Richter σε 20 km εστιακό βάθος, προσωπικά περιμένω και άλλους ισχυρούς σεισμούς.

15/01/2024

Μελέτη Μεταλλικού Ονοιποιίου με υπογειο στην Λετύμπου, Πάφος.

Winery with Basement and Steel Floors (Job N142):
https://skfb.ly/oJrCT

15/01/2024

Στατική Αντισεισμική μελέτη πύργου ανελκυστήρα στον Ύψωνα

Steel elevator (Job N139):
https://skfb.ly/oIPN6

15/01/2024

Κατοικία από Οπλισμένο Σκυρόδεμα με πρόνοια ορόφου. Κολόσσι. Λεμεσός.

Concrete House in Kolossi, Limassol (Job N138):
https://skfb.ly/oOruS

15/01/2024

Μικτή κατασκεύη απο Χαλυβα Βαρεού και Ξύλο Ελαφρού Τύπου. Γερμασόγεια, Λεμεσός.

Steel - Timber House in Germasogeia (Job N140)

https://skfb.ly/oLnFY

15/01/2024

Kατασκευή 4 καταστημάτων στον Ύψωνα, Λεμεσός.

Reinforced Concrete Stores (Job N134):
https://skfb.ly/oGMPT

15/01/2024

Μεταλλική κατασκευή 3 διαμερισμάτων στον Ύψωνα, Λεμεσός.

Steel House Addition (Job N134):
https://skfb.ly/oLK7Q

15/01/2024

Αντισεισμική Μελέτη στο Ζακάκι Κατοικίας Ο/Σ και Ξύλινης προσθήκης. Reinforced Concrete with Timber House (Job N133): https://skfb.ly/oHFp7

01/10/2023

Steel CFS House in Oroklini, Larnaca (Job N126)

Steel CFS House with Basement in Oroklini, Larnaca (Job N126) Type A AgR= 0.25g q behaviour factor = 2.5

04/03/2023

Φαίνεται ότι δεν είμαστε όσο υπερβολικοί όσο κάποιοι νομίζουν...
Η πιο κάτω έρευνα αποδεικνύει κατά κάποιο τρόπο ότι πιθανόν να χρειάζεται επιπρόσθετος ή αυξημένος οπλισμός σε τοιχώματα ακόμη και στα πιο μικρά που φαίνεται ότι αυξάνεται η απαίτηση οπλισμού.
Τα ευρήματα δείχνουν ότι οι γραμμικές προσεγγίσεις MRSA συμβατές με τον κώδικα (Αναλυτικό Φάσμα Απόκρισης και Ανάλυση γραμμικής χρονικής ιστορίας) μπορεί να υποτιμήσουν σημαντικά την μετατόπιση σε τοιχωματικά κτίρια RC-SW.
The findings show that the code-compliant linear approaches (Modal Response Spectrum Analysis and Linear Time-History Analysis) may significantly underestimate the displacement demand in RC-SW buildings.

With reference to a case-study mid-rise building recently built in Chile and designed according to the current Chilean regulations, the study showed that the code-compliant linear analyses (MRSA and LTHA) can lead to underestimating the actual displacement demand in RC-SW buildings. The discrepancy between the maximum displacements and the interstory drifts predicted by the MRSA (the only kind of analysis to which the current Chilean code refers) may be very high indeed. The errors may range from 33% when amplification factors based on the well-known equal-energy rule are applied to more than 90% when no amplification factors are adopted at all (according to the present Chilean code provisions). Even when the corrective formulas proposed by the European Codes or by the ASCE SEI 7-12 are applied, the MRSA was found to underestimate the actual values from 4 to 6 times. This also confirms the very conventional nature of the behavior (reduction) factor for these kinds of structures.

The present study also warns against the danger of local soft-story mechanisms that may affect shear-wall buildings when lower-stiffness walls are present among the much stiffer ones. It must be stressed, however, that only one of the walls of the considered building was found to be affected by damage under severe ground motions, while the redundancy of the other shear walls was able to prevent bad global collapse mechanisms involving plastic hinges in the vertical structural elements. Moreover, it is worth noting that the case-study building showed an overall good seismic performance, as well-designed RC-SW structures are in fact expected to have.

Due to their excellent seismic behavior, shear wall-type concrete buildings are very popular in earthquake-prone countries like Chile. According to current seismic regulations, the performance of such structures can be indifferently assessed through linear or non-linear methods of analysis. Although...

18/02/2023

SEISMIC DESIGN OF CROSS-LAMINATED TIMBER BUILDINGS (CLT)

The provisions for capacity design at the connection level are intended to provide a ductile failure mode characterized by the yielding of fasteners (nails or screws) in steel-to-timber or timber-to-timber connections and avoid any brittle failure mechanisms such as tensile and pull-through failure of anchor bolts or screws and steel plate tensile and shear failure in the weaker section of hold-down and angle brackets connections.

However, the revision of the chapter for the seismic design of timber buildings within EC8 is in progress and will include CLT (Follesa et al 2015; Follesa et al 2018), as is the revision of the EC5 where CLT will be included as a wood based product.
According to the new specifications in EC8, CLT buildings will be classified as dissipative structures with two different values of the behavior factor q for the ductility class medium (DCM) and ductility class high (DCH), respectively classes 2 and 3.

General rules and capacity design rules will be provided both at the building level and at the connection level to avoid any possible global instability or soft-story mechanism at a global level and to prevent any possible brittle failure in the ductile structural elements at a local level.
The general rules will include a general description of the structural system, of the main structural components (walls, floors, and roof), type of connections generally used for the CLT system, and some regularity provisions, also common to other structural systems.
No limitations on the maximum number of stories will be given.

Seismic Design of CLT Buildings in Canada

The CSA-O86 (CSA O86 2016) provisions are based on the assumption that each CLT panel acts as rigid body and that the lateral resistance of CLT shear walls (and diaphragms) is governed by the connection resistance between the shear walls and the foundations or floors, and the connections between the individual panels. Energy dissipative connections of CLT structures need to be designed such that 1) a yielding mode governs the connection resistance, 2) the connection needs to be at least moderately ductile in the directions of the CLT panel’s assumed rigid body motions, and 3) the connection needs to have sufficient deformation capacity to allow for the CLT panels to develop their assumed deformation behavior.

According to the underlying capacity-based design principle, all non-dissipative connections are expected to remain elastic under the force and displacement demands that are induced in them when the energy-dissipative connections reach the 95th percentile of their ultimate resistance or target displacement.
The expectation is that manufacturers of connection systems will make such data available to designers.

Looking at the data provided by the SHARE project regarding the seismic hazard in Europe (Woessner et al 2015), the highest hazard is concentrated along the North Anatolian Fault Zone with values of peak ground acceleration (PGA) up to 0.75 g, considering the results for a 10% exceedance probability in 50 yr. This fault area runs from the southwestern coast of Turkey to the northern coasts of Albania crossing the western coast of Greece and the Cephalonia fault zone, see Fig 1.