Σε αυτό το άρθρο, we will be going over the different types of Mass Timber and engineered wood products currently available in the market and discussing their uses, οφέλη, και μειονεκτήματα. Αν θέλετε να μάθετε λίγο περισσότερα για το τι είναι το Mass Timber, make sure to check out our Βιομηχανική διορατικότητα featuring a Mass Timber expert, and our blog piece on Mass Timber as a Sustainable Building Material.

Τι είναι το Mass Timber?

Το Mass Timber είναι συντομογραφία "Μαζική Ξυλεία", που μιλά σε γενικές γραμμές για διαφορετικές μορφές κατασκευασμένης κατασκευής ξύλου που αποδίδουν καλά ως δομικά στοιχεία. Αυτά τα κατασκευασμένα εξαρτήματα ξύλου έρχονται σε μεγάλη ποικιλία, but in this article, we will be going over glue-laminated (γλουλάμ), διασταυρωμένη πλαστικοποιημένη ξυλεία (CLT), nail-laminated timber (NLT), and dowel-laminated timber (DLT). Γενικά, Το Mass Timber δημιουργείται από μηχανικά κομμάτια ξύλου μαζί για να δημιουργήσει κάτι που είναι μεγαλύτερο από το άθροισμα των μερών τους. Αυτά τα κατασκευασμένα εξαρτήματα καταλήγουν να λειτουργούν ως δοκοί, στήλες, και διατμητικά τοιχώματα σε μια δομή, ανάλογα με το προϊόν.

Τύποι προϊόντων μαζικής ξυλείας

Glue-laminated (γλουλάμ)

Glue-laminated timber is a simple version of Mass Timber that is constructed by taking nominal, sawn lumber pieces, and laminating them together with moisture-resistant adhesives. These laminations can be all of the same species or they can be different, but they are chosen based on strength and other performance characteristics. In all cases, the grain of the wood coincides with the long or length dimension of the timber piece.

Συνήθως, glulam members are used primarily as beams, since they strongly resist flexure perpendicular to their length. ΕΙΔΙΚΑ, they are commonly found in use cases where they sit exposed to the inhabitant of the structure. Because they are length-wise members, they can also make up members of a truss. Επιπροσθέτως, glulam 'panels' can be created to be used as decking, or curved to suit some interesting geometries.

Per the APA, standard glulam members range from 6 inches to 72 ίντσες (wow!) in depth and 2.5 inches to 10.75 inches in width. Γενικά, glulam members are some of the most common Mass Timber products you will find. Βλέπε σχήμα 1 for context on what glulam members look like.

Φιγούρα 1: A pair of glulam beams (kalesnikoff.com).

Cross-Laminated Timber (CLT)

Μέλη του Glulam, Cross-Laminated Timber uses the same lamination techniques as glulam members, but with additional layering and complexity. CLT is made first by laminating dimension lumber together side by side to create a layer, then by laminating layers together to create a CLT panel. Συνήθως, CLT panels come in three, πέντε, or seven layers of dimension lumber, which alternate direction by 90 μοίρες μεταξύ κάθε στρώματος. These panels offer a large amount of strength and rigidity and are obviously found in panelized applications. Areas like walls, πατώματα, and roofs are where you will find these panels.

As a slab or wall, CLT can offer two-way span capabilities thanks to the alternating of layer direction within a panel. In newer applications, it is being added to concrete as a composite building component. Check out the figure below depicting the construction of a CLT panel. Συνήθως, CLT layers range between 5/8 ίντσες και 2 inches thick.

Φιγούρα 2: Depiction of the cross lamination process of a CLT panel (www.sterlingsolutions.com).

You can read more in-depth about CLT in our blog piece Everything You Need to Know About CLT

Nail-Laminated Timber (NLT)

The idea of NLT is more than a century old but is seeing a resurgence in the Mass Timber industry. The geometry of the NLT construction is similar to glulam because you are laminating dimension lumber on top of one another. The main difference is that the laminations are held together by layers of nails, and the number of layers is significantly higher. This ends up giving the NLT more of a panelized application instead of a beam, στήλη, or individual member one. Ετσι, it is used in similar ways as CLT: πατώματα, τοίχους, decks, χρησιμοποιούνται για τον υπολογισμό της επίδρασης του φορτίου ανέμου που ενεργεί ταυτόχρονα σε συγκεκριμένες επιφάνειες, και τα λοιπά.

Due to the panel layers all spanning in a single direction, a unique application using NLT panels is for curves, where the difference between each layer can be offset to fit the curve. Επιπροσθέτως, NLT panels are different because they can technically be created on site instead of only at a manufacturing site, so there is some flexibility in usage there. Check out figure 3 for a live depiction of the construction of an NLT panel.

Φιγούρα 3: Depiction of the nail-lamination construction a NLT panel (thinkwood.com).

Dowel-Laminated Timber (DLT)

The last type of Mass Timber product that will be discussed here is DLT. It's usage is much more common in Europe than it is in the United States. Sticking with the theme throughout this article, the layers of the DLT are made up of dimension lumber laminated together, similar to the glulam and NLT products. What makes DLT different is that the layers are held together by hardwood dowels that run through all of the layers spaced at a certain interval.

The actual structural capacity of DLT panels is not commonly known through its presence in the building code, but the Timber Framers Guild offers information about the calculation. This means that its usage depends on the "Authority Having Jurisdiction" on a case-by-case basis. The largest difference and advantage of DLT panels is that they can house acoustic strips (see figure 4) for specific applications where that is necessary for an exposed wood look.

Φιγούρα 4: Example DLT panel with an acoustic profile on the architectural exposed side (Αποτελέσματα αναζήτησης για).

Πηγές:

1. «Κατασκευή από ξυλεία πολλαπλής στρώσης: CLT Panel.” Think Wood, 30 Παραμορφώνω. 2021, https://www.thinkwood.com/mass-timber/clt.

2. Αποτελέσματα αναζήτησης για: DLT.” Think Wood, 30 Παραμορφώνω. 2021, https://www.thinkwood.com/mass-timber/dlt.

3. Αποτελέσματα αναζήτησης για: Αποτελέσματα αναζήτησης για & Columns.” Think Wood, 30 Παραμορφώνω. 2021, https://www.thinkwood.com/mass-timber/glulam.

4. Αποτελέσματα αναζήτησης για - AWC.” American Wood Council, https://www.awc.org/pdf/education/des/ReThinkMag-DES610A-MassTimberinNorthAmerica-161031.pdf.

5. Αποτελέσματα αναζήτησης για: NLT Lumber.” Think Wood, 30 Παραμορφώνω. 2021, https://www.thinkwood.com/mass-timber/nlt.